First let me say I agree with all of those that believe TV news organizations (broadcast AND cable) have an obligation to report in an impartial and factual manner. But some of the news stories we like and complain the MSM "missed" are ratings losers.
And unfortunately the desire for ratings will always triumph over the notion of civic responsibility.
CNN and MSNBC are getting more like Fox News because O'Reilly beats Larry King in ratings. It is no more complicated than that.
Only when there is a TV version of "Air America" will this trend begin to reverse. Rush Limbaugh started the "commercialization of conservatism" over twenty years ago. It is no longer a dogma. It is a perceived lifestyle, like a beer commercial.