I wouldn't credit Nintendo faithfulls for the Gamecube.....it was their lack of support that made it the least selling console of the gen. Nintendo faithfulls are a minority of grown adults that play Nintendo for the nostalgia. Otherwise Nintendos power comes from attracting new after new generations of children, which grow up and flock to Xbox/PS/PC.
Before haters come in......the only 6th gen console I owned was a Gamecube. I know, whodathunkit?