What's wrong with the media covering every candidate? Who are the media to decide which candidates the people care about? By marginalizing even a single person, you're effectively instituting censorship. Sure, Tancredo wasn't a big name player, but then again, he was never given the chance because of media darlings like Edwards, Obama, and Clinton.
The media is currently force feeding the big four, Obama, Clinton, McCain, and Romney. The vast majority of people didn't have the inclination to go and find out what the other candidates stood for back when they were still in the race, and the media didn't exactly help when it marginalized them as fringe candidates. How do you know that people wouldn't be more receptive if they had the opportunity to hear from those other candidates?
And you're wrong about the media no longer having a stranglehold on information. A good portion of Americans are still glued to their televisions and newspapers for political news, and unfortunately, will gladly accept whatever drivel is presented to them. Political apathy is rampant in this country, and the fact that the media treats every American like an eight year isn't helping much.