I think the bigest problem with digital music is proliferation. There's just too much music out there (already) that it becomes increasingly difficult to wade through everything, looking for something that aligns with your taste.
The future is an automated genre-classification system, which allows you to rate songs. The salient features of these songs are then analysed, allowing for the construction of an "agent" that can bring you new songs that are similar to those you like, kind of like the "more like these" button on search engines.
This does *not* require a centralised authority telling you what genre a song belongs to. Instead, every person can have his/her own agent that you train according to your taste.
One of my students implemented a protoype of this system two years ago, with sufficient success to warrant further investigation.