Viva/4music - Don't want to see Fresh Prince, those two slags and other gossip stuff. Would Heart and Capital cost that much to show? Granted their playlists are a tad repetitive but it's MUSIC not "Look at me, I'm a socialite who opens her legs to anyone" shows.
They probably wouldn't have an audience reach large enough to fund the costs of carriage. The music channels diversified to bring in a larger audience.