Demographics of talk radio, see this link:
http://stateofthemedia.org/2012/audio-how-far-will-digital-go/audio-by-the-numbers/
Scroll about 3/4 of the way down and you will find this:
57% of talk radio audience is 55+.
Only 39% is 25-54.
I'll admit: Conservative talk, in its current form, isn't something I want to listen to. Even though I differed with him on issues, I enjoyed listening to Rush in the '90s. He had some good comic bits on at the time.
I'm also approaching 55 years old in a few years. I certainly hope radio continues to program things I want to listen to when I'm "no longer in the key demographic" (25-54).
But, talk radio skews old. Putting conservative talk on FM has had mixed results, at best, as far as lowering those demos.
By comparison, sports talk and all-news on FM have done much better in the 25-54 demo.
I suppose even if conservative talk doesn't make it on FM, there are shows on both the Internet and Sirius/XM for those who want that.