I feel my ears buzzing.
Anyway, BadSheep pointed at the problem. It's a circular issue. Decades ago, you could only have "mainstream media" directed at everybody because it just wasn't economical to do anything else, so you had to make it one-size-fits-all. At some point though, cable TV and the internet made it possible to make "niche media" better tailored to the ideas of small parts of the population. And people love to be told that their ideas are popular and other people agree with them. So "universal" media, like newspapers and free TV channels who aim at everybody end up alienating most everybody because at some point or another, they'll see their beliefs challenged. And why would you, if you can flock to a niche media that will fit your ideas much better?
I myself am guilty of that- I recently ended my subscription to the largest Spanish newspaper as it lurched rightwards and subscribed to a more lefty online newspaper. And I myself work in an economic daily, which, by definition, is not "mainstream" but rather pretty niche (and yet makes good money, since you can sell better targeted ads to your readers). You can see in the poll how the Republicans, who have many more "niche" media parroting their beliefs (Fox, Breitbart, Drudge, etc) are the largest "media haters". And I'm sure that most of that 50% of democrats would rather watch MSNBC and read Salon.com than NBC or TNYT.
So, in the end, the "mainstream media" is being slowly killed off by an army of small niche media people feel closer to. The result is the inability to understand each other, as our visions of the same events are heavily distorted by who we listen to- which is bad. But, again, going back is just impossible at this point.