^ It's because the Teriyaki Boyz are catered to the Western (specifically US) audience. They weren't really created for the Japanese audience. That's why that song was in the soundtrack, and why they've done collaborations with people like Kanye West and Pharrell, and why they have Western producers.
I've never heard any Asian music over here, besides a few times whenever I'd be skimming through T.V. stations and happen to pass the credits of an anime, which usually keeps the Japanese theme. My husband claims to have heard a few people (I think Ayu and Mika Nakashima?) on a special cable network or something, but I've heard no such thing, lol.
