So someone who bought a home in 1980 before most people even knew what greenhouse gasses were deserves to lose massive net worth? Because if some ignoramus doesn't come along and buy today, that's what's going to happen to them.

We as a society have externalized the costs of carbon emission. That cost is going to fall on someone, whether it's a person who couldn't have known or someone who should've known better it hardly seems reasonably to expect a small group of people to bear the blow.