F-Zero GX sold less than 3/4 of a million. As far as I know, none of the main entries in the Metroid, Pikmin, or Kirby series has failed to break 1mil.
I'm still somewhat surprised that Miyamoto would say what he did. I find it hard to believe that Nintendo was just going to let the series die. I mean, they did include it in Nintendoland, after all.