you can't worry that far out. in 50 years, they could have images that go right into your mind. after that, 3d versions. and all these flat images will just be a, eh so what kind of thing. sort of the way a slide rule isn't even useful as a ruler. i do think copyrights should go free after a while. now if your kids are privy to it, they can extend the license but the timing has to be right and the images have to be worth something. by the way things are going these days, they won't be worth all that much.
only money talks when it comes to govt things. letters don't do much, i wouldn't waste my time. what my things will be worth way in the future is unknown. i can't worry myself about it.
i'm happy we have PD images. i'm colorizing things, and those donated items, not many would have ever seen the light of day.
---Mike Savad
MikeSavad.com