@duncanlock Without researching it, my hypothesis is that “fall into the public domain” became a colloquially used phrase somewhere around the ‘60s-‘70s when huge swaths of feature films and shorts entered the public domain because the studios that originally produced them sold their libraries off to small TV distributors who botched things either by failing to renew at 28 years or leaving out the proper copyright information when creating new title cards as mandated by the sale.