What these guys don't realize is that Limbaugh's real competition from a commercial point of view isn't liberals. It's daytime TV. Seen in that light, Limbaugh isn't such an 800 pound gorilla. Does he out-draw Oprah, Springer, and the soaps?
Al Franken is an insult comedian. He's more the liberal Don Rickles than the liberal Limbaugh.
...And Rickles is actually funny at times.