They Won't Play a Lady-O on Country Radio
pudding.cool
pudding.cool
I would agree that it's not ideology driven, but there is a large risk that the stations are trapped in a local minima. Without more diversity of programming (and ownership), it's hard to know if the old rules are the most profitable rules. With media ownership consolidation, it's harder to add enough entropy to the system to really know.
A quick scan shows me about 10% female singers.