The absence of threads here about most forms of folk music is a consequence of the fact that people with particular interest or expertise in them don't post here, because there aren't threads about the types of folk music which interest them and in which they have some expertise. And if someone starts a thread trying to find out about one of these multifarious varieties of folk music, there won't be anyone to respond with useful information.

That is a tricky vicious circle to break out of. A pity. Myself, I'm interested in folk music right across the board, not just the kinds we tend to concentrate on here.