I don't think that's going to happen. For a few reasons:
- Each new console generation is an entirely different concept as the one that preceded it, aside from maybe NES to SNES, but those early days were humongous leaps in power compared to now. I don't think Switch to Switch 2, with the only notable new 'concept' being "Switch, but now 4K capable," is enough for Nintendo to call it the successor to Switch.
- My interpretation, but when Nintendo says they're in with Switch for the long-haul, that we're just now in the middle of its lifecycle, I believe it. I think it could last 10 years or more.
- Finally, since they announced the OLED model, they now refer to the group of available Switch options as the "Nintendo Switch Lineup." This is in contrast to them previously calling it the Nintendo Switch "Family" of consoles, which is the word they used to describe the Nintendo 3DS Family, when they added New 3DS, XL, 2DS, New 2DS XL. It's a small but interesting and intentional change on their part that I think implies a longer term strategy for Switch, which will later include Nintendo Switch, Nintendo Switch Lite, Nintendo Switch — OLED Model, Nintendo Switch — 4K Model, and of course potential other variations that we won't ever think up on our own.
I think they learned from Wii U that a slightly new feature on top of the previous console, with mostly the same concepts, and even with backwards compatibility is simply NOT enough to warrant a new generation. I think the "Lineup" of Switch models will just continue to grow over the next 5-6 years, and old models will quietly drop off the Lineup until they decide they can't sell any more Switches at the rate it's been going, at which point they'll have a new enough concept to add onto the Switch hybrid premise.