You know what? Sure, why not? I don't think it'll maintain the same ridiculous lifetime 50% attach rate the original had on the Wii U but I think the favorable conditions surrounding the Switch and the Splatoon franchise are going to allow it to reach that 5m mark in Japan -- especially when the sequel is going to be on a console that's going to offer portability and the ability to have meetups with friends; two things that helped Monster Hunter blow up in Japan.