I’m torn on long-term copyrights because of long-running, beloved characters like Mickey Mouse, but I feel like there should be some clause for commercial utilization (or under-utilization) after the original term expires. For example, if Disney doesn’t create any new works in a particular medium for a particular time using Mickey Mouse (as what happened from the 1990s until the mid-2000s or Oswald The Lucky Rabbit since the 1920s), Mickey (in that particular medium: short-subject animation) falls into public domain. Disney is still free to capitalize on Mickey’s likeness in other media, but animation is no longer their exclusive ground. It’s admittedly a hackneyed solution and probably isn’t ideal for anyone, but it’s arguably better than extending copyright terms into infinity.
This sort of “infinite copyright” is singularly important to the Gen Xers and Millennials because, unlike past generations, our epics, our heroes, and our legends may never pass into public domain and those stories might never be retold without express consent of the rights holder. Imagine a world in which Odysseus or even Sherlock Holmes was held in copyright for over 2000 years! (For one thing, Steven Moffat would never have been able to get a job–for better or worse.) Those heroes were to their generations what Batman, Doctor Who, and Han Solo (to name but a few) are to ours. Copyright financially protects the rights holder for a period of time, incentivizing creativity, but extensions into perpetuity ultimately stifle creativity and erode our shared culture.
Source: Copyrights and wrongs