Assuming copyright laws don’t change by then, otherwise there is no way to know.
A plausible answer is 1977 (when the film was released as Star Wars) + 95 years (for pre-1978 works) = 2072. However, the film had been edited by George Lucas for the 1997 “Special Edition” release. Does this mean that I cannot publicly play the Special Edition VHS tape I have at home in 2073 and have to wait until 2092, or 70 years after GL’s death?
George Lucas has been infamously attempting to erase copies of the original movie. Therefore, no HD home video release for the 1977 film exists, however, a fan effort known as the “Despecialized Edition” compiled different versions of the movie from various sources, patching the Special Edition 4K Blu-ray rip to try to replicate the original 1977 experience. Does this legally questionable version enter public domain in 2072, or does this only apply to official (SD) releases?
There is another fan project called “4K77”, which also attempts to restore the original version of Star Wars. They somehow managed to get their hands on the original film reels, and scanned them digitally in 4K. It looks very grainy, but this is to preserve the original experience of watching the film in theaters in 1977.
So if you want a modern-looking and cleaned-up version of the original “New Hope”, then watch Harmy’s Despecialized Edition (keep in mind it’s only 720p). If you want the genuine '70s theater experience with the film grain and everything, watch 4K77.
There is also a release of 4K77 that they ran through a digital noise reduction filter, if the grain bothers you that much.
Thank you, great point!