what's wrong with broadcast networks? what's their problem with bittorrent?

Could someone please explain why broadcast networks don't set up their own bittorrent trackers sharing their movies and series with ads?

Why do I have to download a ripped version of my favorite series (that isn't broadcasted here in Greece) instead of downloading it from the official site together and watch the ads in it just like I would if it was broadcasted?

And if they are not into this business, why hasn't someone set up a legal bittorrent tracker much like they would set up a TV station? They would by the rights to the series or movies and sell ad space in them...