I propose a different approach: the copyright owner can retain copyright indefinitely, as long as they make the work available, in a reasonably practical way, a

I propose a different approach: the copyright owner can retain copyright indefinitely, as long as they make the work available, in a reasonably practical way, and for a reasonable price. I can't tell you exactly what reasonable means here, but it isn't beyond the wit of man to make some sensible rules about that. So, as soon as they lock it away like this, they lose any rights to it. Whereas if they keep making it available, they can keep those rights forever!