If Howlin' Wolf is folk, then rock & roll is folk.

"Classical music remains an identifiable genre, despite the fact that the music of John Cage or James Tenney sounds nothing like Handel. A programme of classical music could include everything from early music to graphic scores, yet still be considered classical."

So Scott Joplin works very well on a classical music program.

No one has commented upon Lomax's statement in 1960 that Louis Armstrong was the greatest folksinger alive at that time. That sort of challenges the claims that commercial music is doubtful as "folk." Since Armstri¡iong was also one of the most commercially successful artists of the 20th century.