Rich, well educated and urban people can and do sing folk songs. Nellie Galt's songs are recorded in the Library of Congress. Her Mulberry Hill, for example, clearly meets any reasonable requirement to be a folk song. Old Nellie lived in Louisville KY and she took voice and piano lessons. I learned a song, "Cosy Mosey," which is a really interesting version of The Cutty Wren that came from Scotland, but had spent 5 generations in Pennsylvania, from a teacher at Duke University. My father went to a boarding school, Andover, and got a degree in chemistry from Harvard, and I promise you that he knew old folk tales and folk songs.
I know Rick Ward's Jobal Hunter, but I can't sing it with his North Carolina accent and style, and I concede that it loses something in the translation. It is a good thing to preserve the old ways of singing ; e.g.,Elizabeth Laprelle, but not all old songs were sung in a peculiar style. My wife's grandfather sang a version of The State of Arkansas, and I don't think I sing it significantly differently from the way he did.