Bruce Murphy nailed it in his summary of the Milwaukee talk radio tempest, Why We Went after Talk Radio:
Conservative talk radio is a different animal entirely. Both Sykes and WISN afternoon host Mark Belling, the two top rated such hosts in town, have expressly declared they are entertainers and not journalists, and have no obligation to present both sides of an issue. Their appeal arises precisely from a lack of good will toward certain segments of the community...
Following the national format used by Limbaugh and the others dating back to the 1980's, these formerly effective mouthpieces built an audience on two bases, the extreme right wing, and undecideds who were looking for intelligent political commentary to guide their decisions.
The last four years through a variety of techniques from providing an alternative progressive radio voice to public exposure of these charlatans the base diminished.
Murphy notes, relying on Dan Shelley's original article, "Secrets of Talk Radio", that the hosts of right-wing talk radio have no intention of engaging in rational dialog.
The nice thing is that the audience for Sykes and Belling is diminishing to the point where no one listens to them, except the true believers and those of us looking for an occasional chuckle or fodder for our blogs.