predictors/variables are rather weak:

1. power - we've seen horse power has never been the deciding factor towards which console manufacturer comes out on top
2. future proof: other than the power argument, not sure there is anything else to it at this point in time (that we know of)
3. predecessor: while this is somewhat true for Sony (with the minor exception that is the PS3), we know that for a fact the previous gen's sales predicts rather poorly new console sales
4. NS & its lack of power/resolution, again, this goes back to point number 1. Also 4K TV these days support hdmi , so not sure why it is claimed that future TV's won't accept its input format, unless the OP meant that the NS's resolution is lower than what is supported by 4(and >)K TVs and as such NS sales will be adversely impacted. I don't think there is a consensus (or the vaguest clue for that matter) around this, not yet anyway

I would suggest wait till more info is available before making predictions, a few other predictors I can think of that might help more than the factors mentioned in the OG post:
price, price, price
ease of dev
targeted segment (the twin console era for example)
etc

Separated for what? Is the Switch actually crossgen?

Does that mean the Switch's successor will also be included in this figure?

Why can't the Switch sales be compared to the PS5 and Nextbox without cutting them in half?

You do realize how much of a mess that will make things if we split up Switch sales. Maybe it looks simple from your perspective, but sales are used for many other things besides comparing consoles.

How about this instead:

Gen 7: DS, PSP, 360, PS3, Wii

Gen 8: 3DS, PSV, Wii U, XBO

Gen 8.5 (Or Gen 8 done right): PS4 Pro, Xbox One X, Switch

Gen 9: PS5, Scarlet, potentially Switch successor

I find it funny this comparison and the same arguments being thrown out every single time. But, the people that throw out these same arguments over and over, have missed the fact that they contradict each other or themselves now.

1 - The Switch will stop selling cause of the more powerful PS5 and Xbox Two.
2 - The Switch is not in competition with the PS4 and Xbox One, it's a handheld or its own thing.

The people who say both these things are right here, on this site. So what is it, is the Switch a direct competitor, or is it not going to be phased by the PS5 and Xbox Two?

Well, when talking about gens, it is time that determines them, not power. If Nintendo continues with handhelds/hybrids, going by power alone, it will take them decades to reach Gen 9, which are probably going to be 10+ Tflops machines.  It's just a silly way to look at the market.  I think Nintendo will probably release a Switch Pro to lengthen the Switch's life, but even that would probably only hit ~1 Tflop.

And to be fair to the Switch, sure it's not that much more power than the Wii U, but like I said, it is also a handheld machine. It being twice as powerful is still pretty impressive. And consumers seem to think so, too. 

Then how about the Wii U being 7th Gen? After all, it has more in common with the Pro/X than a new console: The chip is the same with some enhancements, the games all run on Wii U, the peripherals are the same (and both even came with a Wiimote in the box), it can (well, could now) run all downloaded games from the Wiiware, they kept the name and even the design almost the same. But I'm sure you gonna dismiss that because PS4/XBO launched just a year later, apparently invalidating everything else.

Switch is the same Gen as PS4/XBO, get over it.

Sales predictions for next gen, before we hear details of everyone's pricing scheme, are nothing more than wild guesses. There's also the issue if xcloud and stadia to further muddy the waters. There are just too many variables to estimate anything about the next gen at this point.

Really? Because I got one with my Wii U.

Did the 8GB Version not come with one? Or How come?

I think so too. Xbox and ps5 will get gta6 next gen and switch will not. We all know gta is the biggest game franchise. Xbox one selling 50-60 million this gen without a new gta is very impressive. Im expecting the next xbox to sell at least 85m just like xbox 360

That's odd, I bought the original 32GB Bundle with Nintendoland, and that one had a Wiimote. Hence why I thought all Wii U came with a Wiimote, too.