I don't see any point for Nintendo to release a real follow-up to the Switch. It's about time for them to switch to being a company that makes games and peripherals while everyone switches from consoles to PC and phones. They'll probably try to milk one more generation out of consoles anyway
Discussion
Nintendo's investors would be best served by Nintendo buying 8bitdo right now - not that I care much
If they do go nearly "phone only", I hope they make multiplayer games where you can play a game with people you already know. This category is very unpopulated without connecting to FB, etc.