Advantage:
Those who keep the wolf from the door by charging to entertain spend many hours practising and improving their product. If they had to keep the wolf from the door in other ways they would find it hard to do this.
I don't have a problem with this.

Without those at the top being paid and pushing the boundaries the standard would be much lower (in theory).

There are many layers of commercialism and non-commercialism in folk music. They are all part of the fabric and we'd be poorer aesthetically without them. (And that's from a died-in-the-wool socialist.)