I think this game would have done quite well in the US.
Which is why Nintendo didn't localize it.
I mean, THIS GAME STINKS you know.
Joking aside, I think I read on Tomato's blog or something that Nintendo localized some other game also developed by Brownie Brown as a test to see if Mother 3 was worth localizing. Not only did I not hear anything about the game (I think its called Magical something Star) only a little later and when I did try it out, it didn't feel too good. Why would Nintendo decide to test whether or not to localize a popular game by localizing a game no one's heard of in order to test the American market. In a way, it turns out better this way; Nintendo of America didn't localize the game, they should not receive whatever part of what they usually receive for officially localized games.
Oh yeah, and I beat this game on Friday I think. Really exquisite. I might just replay it on my Wii this time around.