1.) The GBA didn't sell all of its 81.5 million units in four years. It sold over fifteen million units after the DS was released. At the end of this fiscal year, (March 31, 2018) it will be 72 million 3DS to 81 million GBA.

Likewise, GBA software wasn't all sold in its first four years. In fact, the 3DS (369M) will be virtually tied with the GBA (377M) at the end of this fiscal year.

I used first-party software sales earlier because Nintendo makes much more money selling first-party games than third-party games. So the 3DS generation will have Nintendo sell slightly less hardware, an equal amount of total software, and much more first-party software. This is beneficial to Nintendo, because it shows that their first-party games are actually more popular now than they were during the sixth generation. More people are willing to buy Nintendo hardware specifically for Nintendo software, and the Switch is on pace to have one of Nintendo's best first-party lineups ever. You even acknowledge this by saying that this year has a great lineup while listing just four games.

By the way, saying the 3DS hasn't been able to outdo "even" the GBA is ridiculous. The GBA did exceptionally well, selling much faster than the original GB, which only made it to 118 million because it didn't have a successor until its 13th fiscal year. On the other hand, the GBA had a successor in its 5th fiscal year.

2.) That doesn't make any sense. The "concept" of the Switch isn't going to disappear after this year, and it's not going to suddenly become less appealing. Furthermore, even if 2017 has a great lineup (which is a hilarious tone-shift from the beginning of the year, when people were saying the Switch had a garbage lineup,) Nintendo cannot possibly meet all of the accumulated demand from this year. Sales that would have otherwise happened in 2017 will go to 2018 and beyond because Nintendo can't produce much more than 10 million units during this fiscal year. If you want a comparison, look at how the Wii sold in 2008 versus 2007. Unmet demand plus new system sellers like Animal Crossing, Smash Bros, and Pokémon will easily maintain momentum over the next few years.

3.) Okay, so what do you call a portable video game console that will absorb 100% of the software support that Nintendo gave the 3DS?

Also, how does the Switch have more pressure on it in the coming years if it isn't even a 3DS successor? If you just consider it a Wii U successor, it's already a massive success.

Playstation revenue was bigger than Nintendo as a whole in 2016 when Nintendo was basically in a holding pattern for Switch.  And since a lot of that revenue came from third party game sales, which has a lower profit margin, which is why Sony's revenues are way higher than Nintendo's, but profits are closer.  Lets see how these numbers change at the end of this year.

Of course, revenue and the size of the playstation division don't mean all that much as they represent a fraction of Sony's overall business.  Their movie business is bleeding money (which is awesome since it got Spider-man into the MCU), their cell phone line has yet to make a dent in the market, their TV business is struggling, cameras are slumping in general (although the components are doing fine), and I'm pretty sure they no longer have a PC business to speak of.

Overall, Nintendo's assets minus their debts are in the same ballpark as Sony.  The key difference is that Nintendo has enough money to cover their short term liabilities about ten times over.  I don't know where you got the idea that Nintendo wouldn't be able to cover R&D from Switch, but even if they made literally 0 dollars from the Switch, they'd still have had around ten billion dollars.  They would have had to reassess a few things, but they wouldn't be anywhere close to bankruptcy.

Sony on the other hand doesn't have enough short term assets to cover their short term debts.  Which means that in the event of a rough year, they either have to borrow money or sell off long term assets.  If the PS4 had failed, Sony actually would have been in trouble, since that is one of their few divisions that is doing well and keeping the company profitable.  

Sony may have more potential upside simply because they have a hand in more things.  But in terms of which company is more likely to be around in 10 or 20 years, Nintendo is a much safer bet.

3DS barely had competition; Vita only put up a fight in Japan.
You can add both figures and end up with more units, but you shouldn't forget that GBA achieved it's numbers in way less time and it could have done a lot more if Nintendo didn't release DS so soon.

To me, the biggest reason for this is mobile. And i honestly think it's a fair assessment.

Tomodachi? Don't know.
Metroid? Never was a system seller. 
Zelda Switch is coming probably at the end of the Switch's life cycle.
Fire Emblem? Sold really well. But, system seller? Wait and see.

You're right, it does have better 3rd party support from Japan. But at the same time, where are the great titles? We'll get DQ11 someday... 
I admit i don't know much of what sells in Japan, but i don't recall seeing heavy (biggest titles) support from the likes of Capcom, Namco, SE.

To me it's a Wii U 2.0 - with all flaws corrected.
It's not just because you can use it as a portable that it makes it a successor to 3DS, too.

No, my point was that it will be hard for Nintendo to have a year like they are having now.

You are right, part of GBA's figures came after DS launched.
But i don't see that changing my point, which was, 3DS, to reach GBA like figures will have spent more time in the market.
And the reason for that is, to me, that mobile has had an effect on the handheld gaming segment.

Not gonna question your view on 1st party support importance, just want to add that despite that, GBA ended up with a vastly superior library of games (in terms of quantity), very cheap games to make, a number of NES and SNES ports (Mario games... actually there was no original Mario game, was there).
So, 1st party titles might be more important now than before - with reason - but what console made them more money at the end of the day?
I honestly don't know, but given the amount of games and low cost productions, i would bet on GBA.

Why is so weird to think that Switch's concept will become less appealing? Didn't that happen with Wii and Kinect?
It's only natural that the concept looses "value" in comsumer's eyes, over time.

I'll still call it a home console with portability added to it.
The support being more or less, has no say on what a product is.

The pressure comes from the fact that Nintendo only has - so far - one product to carry them over.
Also, Nintendo already said they weren't working on a 3DS successor. Which means that in the coming years, Switch cannot fail.
And it's not just that, in terms of revenue - or profits - it makes a difference in having 1 or 2 products on the market. 

I do consider Switch, when compared to Wii U, a success... so far.
I believe that they still need to show they have what it takes to keep Switch significant in the coming years.

Nintendo was never doomed no. Everybody know anything about finacials knows this. But people though they where gonna drop out of the home console race, since they had a snowballs chance in hell to beat Sony. Switch while great (first console i preordered and bought day 1 since PS2) is not a really a home console, but more of a handheld, which is a market they have dominated since the GB.

The direction Nintendo is going now is excellent though, not only did they play 100% to their strengths (handheld market) they finally branched out and released games for anything but their own consoles (mobile games) something they've never done before. I think the future for Nintendo will be bright and since more and more people are migrating to PC, i wouldn't be suprised that the only thing you will be playing in 2 generations (PS6) is PC, mobile/tablet and some form of Nintendo platform.

Japan is one of the core pillars of portables as the bulk of support comes from Japan, Vita not only took a chunk of that support but the Vita's sales are units taken away from 3DS and in total these units sold are higher than the GBA in the era of mobile something GBA never had to deal with, had Vita's sales been 3DS sales you wouldn't even be arguing about GBA as 3DS would have higher sale than it. GBA would also never have done much more numbers because the PSP was on the way, DS had to come out because GBA would not have held the PSP at bay and risk losing the portable market to Sony.

Tomodachi sold 5.5m and caused massive sales in Japan, Fire Emblem caused sales spikes especially in Japan Nintendo have classed FE as a Tier 1 franchise now because of the effect it had.

Titles like NMH3, Fear Effect Remake, DQXI, Shin Megami V, RE:Revelations double pack, DQ Builders 2, Tales of, Ateliar and so on have been confirmed, support in Japan is far stronger than before. It doesn't matter what it is to you because objectively it's a hybrid and successor to both, yes it being portable makes it a successor because it's the next portable line, like I said before you can keep telling yourself otherwise but it won't change the truth.

Even if 3DS+Vita > GBA, you can't deny how long it took to reach those numbers.
Also having 2 products on the market also means that you'll attract more people, specially in this case where the libraries are significantly different.

Well, if GBA sold 15M more despite having PSP and DS as competition, it seems plausible to think it would have sold much more if the competition wasn't there - or part of it.

The question isn't just how many games are coming.
What drives HW are the big titles. And so far, Switch hasn't a whole lot. DQ11 and Tales of, to be more precise.
Not even the new MH is a main title.

It's almost like what happened with GC, where it had a good amount of titles but it failed at getting the important ones.

It's not me who doesn't see it as a 3DS successor, it's also Nintendo who doesn't even see it as such, despite having 3DS on it's last legs.
Actually, to them it's more of a 3rd pillar, to be honest.

The Switch will be fine next year, the 4 big guns from this year will doubtless become "evergreen" titles next year which will carry momentum without whatever Nintendo is working on next year. Far from resting on their laurels, i'm sure there will be some big titles we don't even know about yet. The Switch can't even keep up with demand in the 4, possibly 5 biggest markets worldwide. When supply has met demand, then we'll talk and when pokemon hits, well i actually expect records to be broken. That's if they will even be able to keep up with demand again.

Except that's a null and void argument because the 3DS/Vita era lasted longer and are still going in a non monopoly era than the GBA, the GBA getting to that mark faster then dying out doesn't really give it any ground as evidently it has been outsold in total portable units.

Many of the titles I mentioned are titles that drive sale that's the point, along with first party titles momentum will be maintained just fine.

It is you who doesn't see it as a successor as you're buying into marketing PR, Nintendo themselves see it as a portable and will handled as such more so than they will as a console. Marketing it as a console is for increased western appeal and to sell the platform at a higher price and sell software at higher prices, believing it's not a 3DS because of PR is like still believing the DS isn't the successor of the GBA.

Nintendo has only been doomed to those that want them to go third party so they can have their games on their systems.

Which is a stupid wish.

They think that somehow Nintendo will just magically go third party with no downsides. They would get their Mario, Metroid, Zelda, Ect on their PS4 ect.

In the most likely scenario, if Nintendo is doomed/failing, they sell of their IP's and you have EA making the next Zelda, or Mario. They have investors to please. Why keep risking making games when they obviously failed before? Why not sell their IP's for the huge billions they would go for.

But lets say they keep their big IP's like Sega and sonic. What are the odds that they keep their developers and full teams in tact? Just cause a company has the same name, doesn't mean they are the same company. I think we can all think of companies that were amazing and now shit, and we only have to look as far as the original team no longer being there.

So please all those Nintendo doomsayers. Think about it before you want it. If Nintendo goes third party, they won't be the same Nintendo, or some other company will have their IP's. And as much as say you might think a say Bethesda Zelda would be sweet, it wouldn't. It would be the same old Bethesda game with a Zelda skin. The same for other games. They would be either just reskins or cash in, meaning no new innovation and we would be on say Mario Galaxy 11.