Nowadays, most people have digital cable or satellite television, systems that feature hundreds of channels, 30 or so of which are neatly categorized digital music channels (rock, rap, etc.) that have no picture and just play their respective music all day.

Does anybody actually watch, er, listen to these channels?

Do you watch the radio? No! You listen to it while doing something else, something active. Radio is a hot medium; television is a cool one. In theory, you don't do anything else but watch a television when you watch television, and eliminating what to watch completely defeats the purpose of television. So what if the music is digital? MP3s are digital too, and you can at least mess around on a computer while listening to them. Watching digital music channels is like listening to porn.