My original reply was mostly aimed at derived works, though I admit I never called that out specifically. I think copyright on the original, unaltered version of anything could and probably should have a very long duration - but should come with a "use it or lose it" provision.
Star Wars, Jurassic Park and Back to the Future are all over 20 years old and still worth a great deal of money even in their original forms without the newer sequals.
Many Disney "properties" are actually adaptations of earlier works - Cinderella is a folk tale and Bambi appears to have been the subject of an unusual copyright dispute.
Of course lets not forget Disney I think Bambi, Micky Mouse and Cinderella have all been continually raking in the cash non stop without a break for over 60 years.
I think this is great! (the adaptions, not the copyright dispute)
However, to enable such cultural re-use, eventually other works need to return to the public domain too, so the next Disney can bring their take on such stories. Unfortunately the trend of copyright duration expansion is locking more and more of our contemporary culture until far in the distant future.
Under the current system. Perhaps if copyright didn't last as long, there would be less emphasis on building a huge franchises that are "worth" so much money.
People spend a lot of time and money creating unique IP and it becomes an asset. Weather they are currently doing anything with it or not is irrelevant as it is an asset that has monetary value.
The day after you create something, certainly. A few years down the line, ok. Twenty years later, it should probably be fair game - if you're in any way creative you'll have made something new in the mean time.
If you want to use it you need to get permission and pay for it
That doesn't have to stop! I think having the original creator bring out a next canonical version will always draw a response. In fact, even now we can see that there is a lot of demand for some "spiritual successors" made by the original creator / team but without the rights, rather than the generic sequel made by whoever the current rights-holder has recently paid to churn something out.
Speaking specifically about games. How many long dormant titles suddenly got reboots when smartphones became popular?
Consider that had George Lucas actually *invented* a lightsabre in 1977, instead of it featuring in a film, by 1997 it would be out of Patent protection and we'd all have thought it was right and proper that the artificial monopoly was broken - and each year we'd be only delighted by the next wave of iteration by our favourite competing arms manufacturers!