Fun poll idea.
I’m not sure if it’ll outsell any of them though. To be honest this game is a wildcard. On one hand it’s “just” a spinoff while on the other it’s finally a 3D open world Pokemon game. So it could be the biggest thing ever or it could be a bog whatever like the other spinoffs. I think many we’ll be surprised either way.
As for the poll, let’s not be too pessimistic, also because things on Switch just sell a lot in general, I’ll think it’ll get to about 16, beating one mainline game.