In the early days of blogging there was a blog called Oh, that liberal media, which regularly exposed instances of liberal media bias. In fact in the early days of blogging that was one of the top achievements of the blogosphere, to point out the easy political bias most supposedly objective news sources engaged in. I used to think that the blogosphere would serve as a necessary corrective to the media, but that hasn't happened.
In recent years, I don't think that the criticism has had the same effect, even if in some ways the media cocoon
has worsened. I think that conservative media critics have convinced all those who can be convinced of the bias and now either people accept the bias because they agree with it or look to alternative news sources because they don't trust the MSM. And the MSM started paying less attention to the criticism. Most of those who were persuadable have been persuaded. (As far as those who deny that such bias exist ... it's hard to deny when prominent journalists
have boasted of the bias.)
But I still believe that it's possible for the media to jump the shark. At some point the media will show that they are so hopelessly out of touch with most voters, that even non-ideological types would cease to believe them.