That's assuming that the current lone model of "searchable mp3 catalog online for $ per song." There are many different ways to profit from music: artist interaction, live venues, merchandise, provide a quality recommendation/review service, etc. The current market is skewed heavily towards what the content that the industry thinks will sell, which receives the bulk of marketing.
Not to mention the fact that the market naturally segments into people of varying levels of interest. People who love music and people who just care about the Top40 can be catered towards by very different business models.
The biggest thing I fear about music is that it is emotional. People want to be in a band and will work for less then minimum wage while living out of a van so they can maybe make it big, but really just to play music. Combined with the fact that in the mind of the consumer a song is near worthless means that the money has to either come from selling massive quantities, aka iTunes and they only break even or something else. And everything that is something else that I have heard of isn't that revolutionary.
Not to mention the fact that the market naturally segments into people of varying levels of interest. People who love music and people who just care about the Top40 can be catered towards by very different business models.