The MSM isn't purposely doing a RP blackout. They are merely soul-less corporations trying to maximize profits. I am sure they feel that talking about McCain vs Romney will bring in more viewers and keep people more interested in watching/listening longer. They don't care about reporting the news, only to the extent that they can maximize advertising profits from doing so.
Bull. Ron Paul could easily be being presented in the media as a classic American Underdog story. He's got a built in audience and they know it. Hell, just promise to mention him on a show and viewership skyrockets. No name local reporters can get national exposure simply by doing a report on him.
To think there ISN'T a media blackout now borders on tinfoil hat territory, except THIS tinfoil hat covers your eyes and ears.
Hell, just watch Chris Matthew's squirm at the end:
http://www.youtube.com/watch?v=Olfc33td05w
Or, consider the fact that Montel Williams got canceled days after drawing attention to the deaths of soldiers when he was 'supposed' to be talking about Heath Ledger. http://www.youtube.com/watch?v=co3Spcq6Uzs
Or... keep believing that the 5 multinational corporations, all with significant ties to the military industrial complex, have no reason to silence a message of peace.