Why do we still have cable?

I was checking some things out on iTunes, and I noticed that we can now download entire seasons of our favorite shows (assuming your favorite shows include only two or three select shows from about eight different networks, four of them MTV-owned) onto an iPod video. Between that and DVD versions of almost every show ever made, there is simply no need for cable, is there? But now without cable, how would we ever see commercials?

It's on its deathbed. Not really, but one can dream, right?