The supply is endless. Talent pool is huge. Millions of amateurs are making music even if nobody is paying for them and are delighted if someone wants to listen them. People are willing to take huge pay cut to earn living doing music and perform in lousy bars.
I think the best model is patronage. Music online is almost completely free and works as marketing to get people to listen. If people like the music and want to hear some more, they will pay in advance for musician to produce it and perform it.
Superstars are somewhat separate category. It's a showbiz and fashion industry where people like what others like to connect. The product sold is famous persona with music.