This whole post reads as extremely ignorant.

First, Iwata is the best business strategist that gaming has ever seen.  He planned the strategies for 5 consoles: DS, Wii, 3DS, Wii U, Switch.  He's got one dud (Wii U), one so-so system (3DS) and 3 massive successes.  And what matters in business is profitability.  We already know the profitability of the DS and Wii blows away anything else, and the Switch has just barely gotten going.  No other CEO in gaming has gotten results anywhere near that good.  Not Kaz Hirai, not even Yamauchi.  Iwata is the best business strategist in the entire history of gaming.

Secondly, a 6 year lifespan is normal.  That is what the market wants.  Things have not changed based on technology.  Both PS4 and XB1 are going to have embarrassing years in 2020 until they release their next console.  They waited a year longer than they should have to release their successors.  A 30-50% YoY drop is normal for a console in it's tail end.  Sony has only avoided embarrassment so far, because it has expanded the PS4 to sell in new places in Europe.  The PS4 will not have too big of a drop next year in Europe, because it is less than 6 years old in places like Poland and the Czech Republic.  But in Japan and North America it's going to be embarrassing for PS4.  For XB1 it's going to be extremely embarrassing next year in every region.

Likewise, the Switch can only put off releasing more than 6 years if it can reach a new customer base of significant size.  I actually think it is going to do this, but only time will tell.  The 6 year cycle on a console is real though.  People get tired of a console after a while and want to move on.  It's not based on technology. 

I can't see PS4 selling only 22 million more from here on out personally. It probably won't be discontinued til like 2022/2023. Sales will slow once PS5 is out but it will still move units for at least another 2 years after that.

A few things. First, no, Iwata was a terrible business strategist. The reason the Wii and the DS were successful was specifically because he followed two business books "Blue Ocean Strategy" and "The Innovator's Dilemma". The minute he stopped following them, Nintendo crashed and Nintneod posted some of their worst earnings in the company's history. He almost killed the handheld line with the 3DS and Nintendo had to cut the price by $80 just to save it. Even then, after 7 years it still sold less than what the GBA did in 4. That's to say nothing of the Wii U. These are both Iwata era consoles.  Any business decision he made was a disaster. He killed the Wii and DS off prematurely, lost all of their western development except Retro (something Yamauchi saw as important), and created the structure of the Pokemon Company which has lost the company billions in potential profit.  

Also, while you can say the 6 year lifespan is bad, you can't deny that is what companies are actually doing. The PS3 and 360 had a 7 year life. The PS4 and XBox One are having a 7 year life. At this point, it's becoming the norm. This is why you have Kimishima saying that Switch will be 7-10 years. 6 years isn't the norm and Nintendo hurt themselves by sticking with the 6 year lifespan. 

I see the arrogance coming from those mocking a scenario where the Switch might need a successor in 2023. As if that's not even a possibility.

Depends on what Sony does going forward. It should be at ~110M at the beginning of next year. If Sony is going to focus on profiting on the HW to subsidize the PS5, keeping it $299 or it only hitting $249 at the cheapest, it'll probably only hit 125M or so.  If they actually cut it permanently to $199 late next year or the following year, I can see it doing 130M-140M.

I still reckon 130-140 million personally; with how well its selling I just can't see it dropping off fast enough to not reach 130m, that'd mean selling less than 20 million after this year and that just seems too little, especially considering it'll probably still be produced and shipped for another 3 years or possibly even more.

Still doesn't change the fact that the Wii (100 million units sold, best selling Nintendo console) and DS (154 million units sold and 2nd best selling video game system ever) was, by far, the most profitable period in Nintendo's history, under his watch. Even if it was followed by their worst earnings in history, it barely put a dent into their overall savings and earnings they gained from the prior generation. And it only lasted for around 3 fiscal years before they were making profits again. Now they've made back all the money they lost and THEN some.

And the 3DS struggling to reach the GBA's levels of has a lot more to do with circumstances that were beyond Iwata and Nintendo's control. The rise of the smart phone/mobile game market that exploded in the early 2010s evaporated the handheld market incredibly. We went from ~235 million DS and PSP units to just ~92 million 3DS and Vita units. A whopping 143 million units *snaps fingers* gone, just like that. And even if the 3DS got off to a bad start, it eventually became profitable and did respectably well.  And as for the Pokemon Company. Created the structure of the Pokemon Company which lost the company billions in potential profits? Dude, you're seriously going to ignore or forget about Pokemon GO? He was one of the key people behind that. Which has led to Game Freak and the Pokemon Company making the most money they have made since the late 90s when Pokemon was on top of the world. 

And I can't help but notice you didn't address Liquid's point about the Switch. That's Iwata. He served as the head developer up until he died. It was his last project, basically. https://kotaku.com/satoru-iwata-put-lots-of-thought-into-the-nintendo-swit-1792378208

And look at what the Switch is doing now. 

So, he's got 4 home runs, (Wii, DS, Switch, and Pokemon GO), a single (3DS), and one strikeout (Wii U). I'm not sure how familiar you are with baseball, but that's a 5 for 6 night, with 4 HR's and batting .833. You know how many baseball players would kill to have a night like that? 

To call him a terrible business strategist is just completely absurd and straight up delusional. The facts and the history just proves you wrong. He had one failure, one "meh" average project, and four winners under his belt. The fact of the matter is, Nintendo was/is in a much bigger and better position during & post-Iwata than they were pre-Iwata.

Right now, the PS4 is down 22.8% YoY from last year. If that percentage holds, then it would finish 2019 with 14,110,050 units sold, which would bring its overall figures to around 106 million. In 2013, the year the PS4 launched, the PS3 dropped 31% YoY. If the YoY drop next year were 25%, with the PS5's launch, then the PS4 would end up selling 10,582,537 units in 2020. In 2014, the PS4's first full year, the PS3 dropped a whopping 57% YoY. Then another 62% in 2015, 61% in 2016, then finally, 70% in 2017. Let's say the PS4 drops 50, 60, 60, and 70% in the 4 years after 2020, that would mean it would sell like this:

2021: 5,291,269
2022: 2,116,508
2023: 846,603
2024: 253,981

So the next 5 years, in total would be a total of 19,090,898 units. Add that figure to the 106 million unit figure it should be at by the end of this year, that would bring it to a little over 125 million units. So, it's actually not that unlikely for the PS4 to finish under 130 million, it's as likely as finishing over.

50/50 chance, both ways I'd say.

First, giving Iwata credit for the Switch is disingenuous. Iwata died in July of 2015 and the Switch came out in March 2017, a year and a 3/4th later. Essentially, Iwata had little to do with the console. Moreso, the only game on the Switch Iwata is credited for is Breath of the Wild. Every other title was made after his death. And even then. Breath of the Wild likely went through many changes afterwards as the game was originally slated for Holiday 2015. Kimishima was the president who marketed the switch, oversaw its launch and was the sole Executive Director on all the Nintendo Switch titles save Breath of the Wild. The Switch is a Kimishima success. Not an Iwata. 

To say the 3DS failed because of smartphones is also silly. The system failed because it had no titles at launch and had a 3D gimmick which increased the cost of the system and sacrificed battery life. This is why they had to cut the price from $250 to $180 because the system was doing so bad. What you don't consider is the importance of Nintendo's handheld line. Even with the Gamecube doing poorly, the GBA kept Nintendo going. The system sold 80 million over 4 years. The 3DS sold about 70 million over it's 7 years. This is in addition to the Wii U which sold worse than the Gamecube. Iwata put Nintendo into a dire situation that it didn't need to be. You gloss over that period of time and say "Awww they made the money back," but ignore that Iwata dug a huge hole for Nintendo that, essentially, Kimishima got them out of.

And what I think this comes back to my first point on the Switch. You want to give all the credit to Iwata because he came up with the idea (maybe), but you forget execution. The DS and Wii were killed far earlier than they ever needed to because Iwata thought "We have to have a six year lifespan" when Nintendo clearly needed another year to get the systems ready (remember the awful droughts that pledged both systems?). The beauty of the Switch was Nintendo made sure there wasn't a drought, and we had games after game every 2 months or so. Theres no saying Iwata would have pulled that off, and he may have easily just released too early and lead to similar droughts. 

Last, on Pokemon, you don't understand what youre talking about. Nintendo now only owns 33% of Pokemon. In fact, one thing that hurt Nintendo's stock rally with Go was investors realized Nintendo only gets 33%. If Iwata was not an idiot, he would have bought out Gamefreak and made The Pokemon Company a wholly owned subsidiary of Nintendo to manage the licensing. Now you have your cake and eat it too. While there would have been more upfront cost, Pokemon has made billions and now Nintendo would have gotten the other 66% of the games. Iwata left billions on the table because he didn't know how to structure the deal. 

I think the issue is you all want to give Iwata credit where credit isn't due while simultaneously ignoring his faults. 

I feel like due to its much greater sales and popularity PS4 will not drop off as fast as PS3 did. It's also made of more off-the-shelf parts so it could go to lower prices than PS3 ever did like $199.