Ever watch ESPN's SportsCenter in high-def? Course you have. The picture is beautiful but there is nothing extra that the HDTV format gives you. When they display stats on the screen you can see that they extend right to the spot that a 4:3 TV ends. ESPN can't give you more info just because you have a HDTV. They would be alienating the non-HD owners.
This has to be the same reason that cable stations have not gone high-def yet. They can give you a great picture but nothing more. Moreover, these stations rely on a lot of cameras that are not in the studio to give you most of their programming so there would be a good amoount of non-HD content on the station.
Still, a guy can dream can't he?