Metroid Prime 3 also sold over a million. Why do you think a remake of Prime 1 & 2 and Metroid Other M are being released this year and the next?
If a game sells well enough or even better on the Wii that means that developers and publishers made a profit out of it. Which means that they will most likely make sequels or games similar to them. That's why the Conduit, Grinder, Red Steel 2, Metroid M, No More Heroes 2, Sin & Punishment 2, Silent Hill, Gladiator, etc. are all being developed for the Wii and the Wii only (excluding Silent Hill). Do you really think Red Steel only sold because it was the 1st FPS on the Wii? Why would Ubisoft be making Red Steel 2 if they thought Red Steel was just luck? Do you really think Red Steel 2 wouldn't sell over a mil? That game alone makes me want to get my Wii fixed but I'll probably get it fixed really soon cuz WiiMotion Plus games are coming out.