Puzzling

I understand snafus that result from rights ownership when it comes to television properties. What I don't understand is why contracts aren't written in such a way as to ensure that, five or ten years down the road, content based on the franchise can't be created in a new form, such as a series of novels, regardless of current ownership.

My point is that I don't understand why novels based on Deadwood and Twin Peaks don't exist, darn it.