Contrary to popular belief, the media is not liberal. Biased, yes. But that is on both parties parts.
The news media today is about ratings before anything else. The powers that be do not care about how "liberal" or "conservative" a station is, as long is it generates them a large revenue, they will continue to spew out the same thing.
The news media today is more about entertainment. To conservatives, it is entertaining to hear people such as Hannity, O' Reily, and Limbaugh say things that they WANT to hear. And the same could be applied to liberals as well with Olbermann, among others.