Television shows and movies don't have nearly the timeliness factor sports broadcasting has. If I see guardians of the galaxy a week after it comes out it doesn't really matter, but there's very little point in watching 'the game' even a day after the fact (unless there's some exceptional reason to).
So in some regards, they do have kind of a stranglehold and are holding out hope that they can capitalize on that. It's funny talking to cable subscribers < 40, because (obviously anecdotal) the majority of the reasons given are 'how else am I going to watch sports?'