Thinking about it, one of the reasons the call-in talk show format got popular is because it is live programming. Radio listeners didn't just start demanding people screaming and saying shocking things--though many of them were certainly looking for a way to get on radio and speak their piece. I believe that the live element is what grabbed listener interest. Consider the success of Gary Burbank on WLW. He's not one of the angry white men--but he is live.
Live programming is, of course, where radio started. It makes one wonder if more live programming--of a different type--is waiting in the wings as the angry white men duplicating one another's shtick fall away. It seems as if everything comes back if you wait long enough ...
For some interesting background on all this, have a look the book Something in the Air, by Marc Fisher. You'll find my review of the book here.