They have many ways the can make a Switch 2 a viable successor. Just expand on the media aspect with netflix, a more customizable OS and better online and it would be worth it for millions.
They won't have problems making games for 1 system and supporting it properly so unless they really fk up their marketing for the next console i don't see it flopping. Now i don't think it can repeat the freshness of the Switch that is beating records on so many levels for Nintendo. But i think it can still manage to be atleast on the level of the 3DS