Somewhat in response to Victor’s comment: being in the role of a music producer gives one the means to creatively use the medium for music itself and its packaging / distribution. It’s true that some musicians don’t want to do (much) more with the web than sell or give away some audio tracks, but to others, the web is more of a new medium for music than not.
So, the Internet Archive has a couple ideas about what music is on the web. Other services have some different ideas. But, there is a big gap between what these services offer and the hands-on music production* process that musicians engage in / cound engage in, with the web in mind.
* production being potentially the full process from conception to “final” output