Looking past cm454's condescending reply, regardless of what you think of my theory, I still say the only reliable way to judge what people want to hear on the radio is to actually study what they are listening to.
I think we can agree that in most parts of the country it's the conservative talkers that are drawing the big audiences. It's not a myth that Rush Limbaugh is the most listened to radio personality on the planet. Hannity, Beck, and Savage aren't far behind.
What are they doing that the liberals aren't? This is just a guess, but I think it's because conservatives are more fun to listen to than libs. Agree with them or don't, conservatives can be outrageously funny and entertaining. Libs, for all their closeness with the entertainment industry, have no idea how to put an entertaining talk show on the air. No clue. It's just beyond them. They come across as hapless whiners.
In my opinion, this why liberal talkers can't draw flies or get arrested in most parts of the country, including mine. Many owners and programmers won't go near them. I live in Houston and it's been so long since Houston has had a liberal talker I can't even name one. I have no idea who today's liberal talkers are.
But, the airwaves would be saturated with them if programmers could be convinced that the audience and the dollars are there. Money is the only language programmers know.