I'm not McCall. I fully believe in innovation so long as it works. To my ears, folk-rock does not work. Folk songs (and the style in which it is sung) clashes with rock rhythms. The monotonic style of guitar playing borrowed from the blues and adapted for the use of folk music is a success. It sounds right to my ear. But then, it depends on the ear of the behearer. As far as I'm concerned, rock was incorporated into folk music for purely commercial reasons.