This could lead to a broader culture, because the most popular works would get long copyright protection terms, while the relatively unpopular ones would get short protection terms. People would be more likely to use those unpopular works and perhaps breathe new life into them.

Eg imagine if this is how the system worked right now. You could have streamers watch unpopular (modern) movies with their audience. Or a youtuber could read a book to their viewers (listeners). And it wouldn't have to be content that's 100+ years out of date.

You could also make it so that when the copyright protection first expires then a percentage of the income earned through the use of the work gets paid to the author for some number of years. Eg you're free to use the work, but you've got to pay some percentage of the revenue to the author for 10 years.