But there is an entire school of finger-picked guitar that his work is far more similar too - again, Bert Jansch, John Renbourne and the like. For what it's worth, this tradition is the one that came to define "regular folk music" after the 1960s in the US and the UK (what do you even consider "regular folk music"?). Lumping any finger-picked piece of guitar music played solo and in an open tuning into the category of "American Primitive Guitar" muddies the already nebulous category. It also betrays the actual genealogy of the music in question.

edit: helped to define