I'd guess you have to have a very particular combination of qualities to persevere as a professional folk singer/musician - only one of which is being a good folksinger/musician.

As an artist, without bragging, I know I'm as good as many who are at the top of the 'paid well for it' heap, though not as good as some. But I don't have the kind of ambition the top o' heapers have, nor the business smarts, nor the dedication to live in the right places and schmooze with the right people and follow the most recent fashion. At times in my life I've envied those people for having the traits I do not; other times I've been a bit scornful of them for sometimes 'selling out'. But for the most part, I just understand that they have been willing to learn and do things I haven't - more power to 'em.

I imagine there's a lot of the same dynamic in the folk music world.