This thread, https://boards.straightdope.com/sdmb/showthread.php?t=683013&highlight=film+rights&page=2 covers some of the same ground as this one. And this film seems to be the leader at ~100 years:
On the other hand there are numerous movies lost to fires or destroyed (sometimes melted down for the silver content) to make room in the warehouses.
Wikipedia article: https://en.wikipedia.org/wiki/List_of_lost_films