It’s crazy to think of how many 10M-sellers the Switch will have. Odyssey is already there, MK8D will hit the mark this fiscal year and BOTW will hit the mark next fiscal year. On top of that, Pokemon will hit the mark (probably twice) as well as Animal Crossing, 2D MARIO, Super Smash Bros. and so many more. I could see the console’s top 10 best-sellers all above 10M if Nintendo really supports the console for 6+ years.
The Wii had 10 games that sold above 10 million; given its insane software sales thus far, I think Switch has a pretty good chance of beating that.
Odyssey is already there, MK8 and BOTW are a lock, Splatoon 2 very likely as well, then there's Smash, Animal Crossing, 2D Mario, Pokemon...
We're really in for a game, huh ? :)