There's the "Pro" argument, that we might get a half-gen refresh, but with the Switch's success so far, I doubt that will happen.
Streaming is at least another gen away (if not more). Ditto VR, if it catches on.
Soooo...really, it looks like their present niche is positioned to keep working for another few years. 2022-ish, they make a Switch 2.0 that basically allows for portable PS4/XBone performance, with enough modern GPU features to get a few (but not nearly all) of what will be "current gen" PS5-level games. Nintendo makes their usual exclusives. Third parties port older games.
The only question is if Nintendo is too restless with the idea of essentially running it back.
Nintendo needs some thing that will make gamers go wow and blow the competition out of the water. I am not sure how much longer the Switch and Switch Lite will last with all the technology changing so fast.
I think they should stick with the switch concept as thatâ€™s all they have going for them. I personally believe if Nintendo were to go back to releasing traditional consoles + handhelds theyâ€™d be doa. Maybe not the handheld, but the home console would be. Iâ€™m also fairly certain this was their endgame when they decided to merge handheld development and home console development during the Wii U era.