Nintendo has published 55 games on Switch that have sold at least 1 million units

[Torpoleon]

Doesn't help that they released NSMBU DX only six months before SMM2. I don't consider SMM2 a failure, but I would've expected 10 million by now if I were predicting sales when the game first released. Either way, I do think it will be a 10 million seller eventually, but probably just barely.