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…