You say that because people are capable of choosing from a variety of many sources, they are more likely to ignore sources that contradict their point of view. I'm not sure that's how it works. If someone is set in their way of thinking to the point that they will click the back button, I think they'd be just as likely to put down the paper or turn the tv to another channel.

The good thing about having many sources is that if people are actually searching for the truth, they will be closer to finding it, simply by seeing many perspectives over one to a few.

If the mainstream media is being deceitful or otherwise incompetent, I'd hardly see that being useful for a common reference point.