"The general consensus amongst people ...."
Nope - 'twasn't the way it happened - the decline was pretty well documented at the time, particulary with the correspondance following Fred Woods' article 'Crap Begets Crap' in Folk review - it was the core audiences that left; we never really managed to attract enough curious outsiders in - when your lot moved in big-time, the regulars left.
Quality certainly came into; Alex Campbell's "near enough for folk song opening line ceased to be a joke and became a reality, and now, to some clubs, seems to be an essantial part of their make-up, "so as not to frighten away the laess talented".
Jim Carroll