Do note, I believe that this discussion has little to do with Piracy. While a thing entering public domain would mean that it could be distributed freely, I'm largely concerned about the creators and their ability to remix existing properties, as unfortunately, you can't really pirate copyrights. Everything created based on another's work (which lacks special permissive licensing) is always dancing on the knives edge of the owner's whims.

With the system as it is, anything that released when you're a five year old, you can only legally remix it when you're so old you can't remember it anymore. (And that's if you're lucky)