I am a little confused by some of the replies. Yes, of course, local channels carry national network programming. The point is the national programming is just that national, it’s all the same. So, why do you need to have 500 HD channels all showing Lost or Desperate Housewives? For that you only need a few HD channels to allow for the several time zones. Do people really care if they are looking at the feed from NY or LA? Do you want their local ads? They can switch to the local SD station at 6 or 11 for the news. I am missing something?
The locals and FCC do not allow this to happen.