Matt's list includes a number of clubs that don't promote themselves as "folk" clubs. Maybe that is the key to their success.

When I count up the clubs in areas where I know the history I don't see a significant decline in numbers of venues. I do see a decline in audience numbers per venue and a move from booking guests to singarounds.

I interpret that trend as a switch from clubs intended to promote folk music to a wider public to clubs intended to provide their members with a place to sing. Both approaches are equally valid but the "problem" is that people go to one format expecting the other and are dissapointed.