For better or for worse, Pokemon is in the same league as something like COD where it will literally always sell insane numbers.
Personally, I don't like annual releases. I would rather developers be given more time to polish games and release them in a better state. That would be better for the devs and the fans. But the Pokemon Company has pretty much no financial incentive to do that so I can't really blame them.
Also while gameplay is far more important than graphics in my eyes, it's clear that the switch is capable of far better visuals and performance.