I agree with you. I'd love to be a part of a solution, but it would take some serious commitment and big-backing. At least, as you say, on a social level - through HN and similar communities.
There is a good solution, and it'll solve several other problems (some way more important than copyrights). I just don't know how to implement it - does anybody have any idea that does not resemble Ucrania?
If you look closer at that list, the most recent film to enter the public domain was produced in 1968. The last time a film entered the public domain (known at least) was in 1991. And the overwhelming reason any work actually entered the public domain was that they failed to renew the copyright (which implies they could still not be in the public domain if the creators were more on top of their copyright situation).
I think what the GP meant with "public domain does not exist anymore" is that it is effectively is no longer relevant.
There has to be a good solution.