Spider man sales are pushing 5 million after a month. It's going to hit 10
Smash 4 combined sales was 13 million on a combined install base of around 85 million, which included people who double dipped. Roughly 15% attach rate
Switch has about 22 million units sold. Even if Switch sells another 20 million units, and attach rate goes up to 20%, thats still only 8.4 million units. If Smash beats Spider Man PS4 it will only be because both the game and the Switch itself have really really really strong legs and it will happen 5 years down the road when they're selling Spider Man 3 on PS5. It's not happening this fiscal year.