Here's an additional idea to shorter copyright periods (not mutually exclusive). Weaken protection for a copyrighted item over its duration.
For example, when the subject is first copyrighted, it enjoys all the protections we have today, but say at different time periods (6 months, 1 year, 2 years, 3 years, etc.) more things become fair use or public domain.
As a simple example, take a copyrighted song. When first registered, it would have all the protections known today. But suppose that after awhile, the allowed cases of fair use are extended.
So at a certain point still within the copyright period, people may be able to use certain bars of the song. And eventually people might be able to do their own covers of the song, perhaps more/earlier fair use is granted for those not earning money on it, e.g. your YouTube fan videos. And at a certain point, people can start using parts of the song in other works that are not wholly dependent on the song, such as use in a background track to a small segment in in a YouTube video like the credits out-tro.
For example, when the subject is first copyrighted, it enjoys all the protections we have today, but say at different time periods (6 months, 1 year, 2 years, 3 years, etc.) more things become fair use or public domain.
As a simple example, take a copyrighted song. When first registered, it would have all the protections known today. But suppose that after awhile, the allowed cases of fair use are extended.
So at a certain point still within the copyright period, people may be able to use certain bars of the song. And eventually people might be able to do their own covers of the song, perhaps more/earlier fair use is granted for those not earning money on it, e.g. your YouTube fan videos. And at a certain point, people can start using parts of the song in other works that are not wholly dependent on the song, such as use in a background track to a small segment in in a YouTube video like the credits out-tro.