About 120-130, maybe 115. It'll be like a Game Boy/Game Boy Color to Game Boy Advance decline.
I don't think we'll see DS to 3DS or PS2 to PS3 declines by percentage. And Wii to Wii U is nearly impossible.

I feel like it's way too early to give an exact answer; we still don't know its price or software which will be major factors, or how long it's life will be.

Just going off the hybrid form factor and expecting the usual Nintendo franchises and third party support equal to the current Switch, I'd say 120 million is the floor, but if it has some unexpected breakout hits, better-than-Switch third party support, an affordable price point, and lasts as long as the current Switch, I'd say 150m plus is on the cards.

The only problem here making those kind of predictions is the lack of insight into the actual future the next console will launch in.
Considering the clowns in the US office thinking of the tarrifs bit could definitely impact a part of the US Switch 2 sales long term.

Aside from that, I'm really expecting something similar to the SNES in terms of proportions (like most would for what is an iterative device).

Although, launch aligned it looks like it could get the early lead on its older brother going by rumored forecast.

Nonetheless, we're never under the looks of a pleasant surprise or a deceiving one.

It'll realistically sell somewhere between 100-180 million lol. Decent chance it beats the PS2. Zero chance it's another Wii U. I'll make my final prediction close to launch.

Right now? I predict it will be a 2 to 173 year generation with zero to dozens of killer apps that will drive between 1 million and 37 billion sales.
But I'll let you know when I have more information to narrow it down a little.

If lying Ryan alway finds some used PS2s in the toilet, refurbishes it and adds it to the total, no wonder! 

For the Switch 2 we cannot say anything! I guess 30- 50 million LTD is guaranteed at this point! Fact is: The Switch is synonymous to mobile gaming! Its a famous brand on a Level with Playstation (2). Switch stands for handheld gaming in console quality, it depends if they can carry it to the sucessor. First reactions have been overwhelmingly positive! The reveal had more viewers than the PS5 unveil wich is a good start but it does bot tell the whole story! Nintendo promised something in those 2:22 minutes! Now they got to deliver! It all depends what Nintendo will do in the first year. 2025- 2027 there will be a lot of cross gen titles for the current Switch, at least from 3rd parties, i guess they won't fully focus on Switch 2 before summer 2027! Its too early to tell right now. 

Simply the fact that it's a Switch 2 and everything looks fairly promising, if a bit safe, so far means it has a very good chance of hitting 100m+ unless they fail to deliver compelling exclusives.

Most likely will be a massive success, although the Switch is a tough act to follow, since the Switch. The Switch had excellent software support, partly due to the fact it basically got every Wi U game. Switch 2 will not have that advantage. The Switch also was a very innovative product, the Switch 2 is much more safe.

LOL @ anyone selecting under 20 million!🤣😂

I think it will have a very successfull launch, probably outpace the original Switch for 1-2 years but ultimately end around the 110m mark.