Good thoughts about a question we never get tired of. I am reminded, though, of a comment made by Thelonius Monk when he said that "...writing about music is like dancing about architecture." Labels and definitions do tend to get in the way of how I personally relate to music or to any other art form. In terms of how it makes me feel, I can't put into words a big difference between "folk" and blues and jazz and country and even classical music. Easy to talk about individual songs or performers, but not categories, if they exist. Not saying it should be that way for everybody.
Veteran of several twelve-step programs regarding music, Chet.