Maybe we could try to go back to running hosts/programs that are actually interesting and entertaining to listen to, instead of trying to have 24 hour talk stations that will air pretty much anyone or anything just to fill the time? There used to be many stations that were talk programming during drive times, or just aired Rush and played music during the other dayparts. Would that work today?
The problem with that approach was that Limbaugh tended to chase off the music listeners. Those listeners went to FM and eventually stopped coming back to the full-service AM station altogether. You might be able to get away with that in small markets, but, when music listeners are offered several options that don't break for talk for three or four hours, they tend to prefer those options.
Talk radio used to be a place where you could get a little bit of this and little bit of that. Certain times of the day offered news, while others offered politics, others had sports, and yet others had financial talk. I worked at a station like that about 25 years ago. We had a local news and talk program in the morning, a local show that paired a liberal and a conservative together to talk about various issues, Limbaugh, a local evening news program, sports talk in the early evening, Bohannon in late evenings, and Art Bell overnights. Weekends had a few local programs on various topics and a lot of financial talk. The increase in conservative talk tended to happening gradually, at least until Cumulus bought us and began the corporate cram down. Some of those changes happened because programs went away, and conservative talk was increasingly the only option to replace them. We also went through about three PD's in a year, and each tried to make their own mark on the station. The last one of those three felt like talk radio had evolved into a conservative media, wanted us to have a more major market sounds, and thought going more conservative was the way to achieve that sound. Didn't hurt that he had worked down the hall from a Top-50 market conservative talk station that was originated much of its programming. He thought those people are great and wanted to use syndiated offerings that included those people. Then, Cumulus came in and started replacing our other shows, especially those at night, with its own programming as contracts expired.
Your post gets to the heart of why I started this topic. Right wing talk is getting more and more extreme and the demos are getting older, so why do we see so many in larger markets, and a few new launches?
I tend to think it's an effort to manage the slow but inevitable decline of AM radio as a viable content delivery system. The audience is getting older, but it has roughly double the number of avails as music formats. Plus, what few 55+ agency buys that exist go almost exclusively to talk radio. As you and some of the others have mentioned, you don't see many new launches. One of the reasons for that is because running conservative talk on FM usually creates an older skewing FM station that's tough to sell.