If I own a Picasso I can absolutely burn it if I want to. Don't like it? Buy it off me before I do, or don't sell one to me in the first place.
[1]: "In most instances, the rights granted under VARA persist for the life of the author (or the last surviving author, for creators of joint works)." https://en.wikipedia.org/wiki/Visual_Artists_Rights_Act
It is about rules elaborated by an educated society. Not perfect rules, but at least rules that preserve what this society consider "important". Many example show that humans that live in a given place are very well aware of how important is a "healthy" ecosystem and give rights to "a good life" to this ecosystem: Wanganui river in New-Zeland, lac Erie in US (this attempt failed), constitution of Ecuador, etc... Elinor Ostrom wrote interesting about this rules (governing the commons), she had the nobel prize for that.
And those gluing this hands to valuable old master paintings are still imbecile puppets, no matter the alleged reason to do it in their minds.
Sure, spending million on 'priceless' art... while spending as little as possible on preserving our ecosystems?
Many arts museum's are private. Its duty is to preserve important human culture artifacts, not to save the planet.