Some people can get local Salt Lake City channels OTA via translators located in my area, but my house is located in a neighborhood that cannot get those signals due to the area's topography so they are not available to me OTA. We have one full power local NBC affiliate, KENV, transmitting from another location which I can get in HD OTA. Directv doesn't carry KENV for some reason but carries the local Salt lake City NBC affiliate instead in SD. The local Salt lake City channels that I only get in SD are available in HD to Directv subscribers who are located closer to Salt lake City. I believe that the same situation applies to Dish subscribers. I can't get cable in this location either. However even though my area is considered a part of the Salt Lake City coverage area Directv's HD spot beam doesn't reach far enough so we are stuck with SD only. I am advocating that people in our situation be allowed to get the national network feeds in HD. It seems like a reasonable enough request to me.
As far as "DirecTV is refusing to carry them" goes, actually they refuse to set up their spot beam so it reaches far enough so that people in my area can get locals in HD. Perhaps it is not technologically feasible to do that. I don't know. But again that's why I am advocating being allowed to get the national feeds in HD.
If the problem was the fault of the local station, then I would agree with you, but in this case, it is clearly DirecTV's fault. If the rules were changed to allow national feeds because DirecTV does not want to spend the money (or whatever it is that prevents the spot beam from reaching you) to provide your locals to you in HD, the local channel should not be punished. To allow DirecTV (or Dish) to give you national feeds in HD because DirecTV (or dish) does not have the local stations in SD would ensure that DirecTV would never provide any locals in HD.
On the other hand, if the locals do not agree to provide the HD signal to DirecTV or for some other reason do not allow DirecTV to carry the locals in HD, then I would agree that the law should be changed to allow DirecTV to give you the national HD feed.