On another angle, there's a long history of music technologists trying to create formats that allow music to be released as an interactive medium. When quadrophonic and then multichannel audio formats were developed there was talk of releasing albums in multitrack format to allow users to do their own mix. Same with multimedia -- one of my CEOs used to go on about multimedia meaning listeners could "conduct" classical music.
This failed for two reasons. One was copyright problems. The other was that a lot of the value of music is in the mix and the mastering -- basically, most people can't be bothered to do it, they like having the finished article. The AIFF-quality files required would probably be a bit big for 512K broadband.