I'd be surprised if anything was played less on radio than folk music! ;-) But it's hard for me to know, because I don't normally listen to radio anymore, and basically haven't since the early 70's. I listen to CDs and records. That way I choose what I get to listen to, you see, and I don't have to put up with a barrage of commercial advertising and other crap I have no interest in.

If most people were like me, the radio and TV stations would be out of business. They'd be defunct. Or else they'd change...and quit being just a vehicle to flog consumer products.