I like the idea that any IP created in my lifetime can stay in control by some entity from a consumer standpoint. Take something like Star Wars, once that enters general domain than there is the possibility of "Star Wars" being taken in a ton of different directions and makes it harder for a fan to follow since they will effectively be competing with eachother as the true "Star Wars".
Personally I don't exactly know what a good timeline is, but I don't fully understand what exactly the harm is of some entity being able to keep control of something for a certain period of time.
Or am I missing something here?