Something amazing is about to happen. I'm not going to try and justify this myself. I will simply quote the following, taken from the Billboard.com announcement, made a short while ago:
Most recording artists would love to have their music available on MTV Networks' "Rock Band" videogame. But MTV's Harmonix unit, the developer of "Rock Band," simply hasn't had the time or staff to program the vast number of songs it would like to include in the game.
That's about to change. Later this year, MTV plans to launch a groundbreaking initiative called the Rock Band Network that will enable any artist-unsigned emerging act, indie cult fave or major-label superstar-to submit songs for possible inclusion in the game.
This is only a fairly small selection of the full announcement, for every detail please see the link below.