Miyamotoo on 18 April 2017
Well everything is possible, Splatoon 1 sold 1.7m on 3.3m Wii U consoles in Japan, that's more than 50% attach rate, and Switch will most likely end up selling much more than Wii U sold. I think Splatoon2 will be 3m+ game in Japan, so even 5m is possible.