Nintendo isn't just about sales all the time. And Metroid is one of its core franchises.
It also comes down to Nintendo trying to make a game that appeals to the 'core' market as well as the western market. And Metroid has always done that.
Pikmin was more of a fun original game Miyamoto made that gained a small fanbase. And it'll get a sequel eventually. But Metroid is a 20 year old core series.











