The commodification of folk music is a different issue to the money thing. When the public twigged some singers were better, knew more songs and played their instruments in tune more often than the chap in the Grey Horse - and you could see him two stations along the line for thruppence - the game was up for Old Ned at The Nag.
Somewhere along the way folk music moved from being the music of the people to an exercise in connoisseurship. Once the shortcomings were dwelt upon as exemplary by the 'informed' it wasn't folk any more. Folk revival is not folk in the true sense and it's crazy to describe it in those terms.