I can recall as a kid thinking album notes along the lines of "I learned this from the singing of ***; it is an old Scottish border song" or "*** collected this song in *** where it has been sung since the early nineteenth century by the *** there" were a waste but now a song seems quite naked without that much; and the spoken "learned from the singing of" to me seems a very graceful way of recognizing a source/collector/arranger and also recognizing the folk tradition itself in performance. (Even if "the singing of" was on a CD, or a tape in the Smithsonian, or a radio show.)
Paying people for their work is a different proposition and must be done properly.