Im sure that they will be broadcasted, its just that the nationals arent as big as the "Supercross Spectacle" in the eyes of networks and promoters. I agree with you in that I prefer the nationals myself. But TV and promoters like the hyped up stadium show atmosphere of supercross so that deal is always easier to lock in. I did hear somewhere that speed may pick up the Motocross TV package as well but that was awhile back before the SX season right after they announced they had the SX TV package with CBS. I havent heard anything since.
Here it is, I just saw on AMA Motocross that OLN has picked up the contract to air the Nationals again this year. It sounds like a similar package as last year, but with some new announcers. They say the delay in coverage is better, but it looks like each race will air about a week later on the following Saturday and Lites class on Monday so not really much better if any. Anyhow here is the link: http://www.amamotocross.com/article.php?UID=OWyn1K2551xuAT7TkCswEIkVCN0EeZ&sc=1003&aid=7603