Pete Seeger and Dolly Parton are interesting examples, presumably picked as Seeger would be thought of as on the folk side of the divide, and Dolly Parton on the country. Yet Dolly Parton was of course from the real world of folk music in the Appalachians, with the music totally in her blood, whereas Pete Seeger was from a posh, totally non-folk background and learnt to become part of(or to create) the folk revival. Learning guitar licks from the servant, even. A complex mixture.