The point is: Michigan stadium is not on the same level as those other constructs. This Facebook user is doing the equivalent of “It took 5 years for my city to approve permits and build a new library. Extrapolating from that, it should have taken 400 years to build the Hoover dam. Aliens must have done it”

What you’re looking for is a revocation key. You can generate one in GPG at the same time that you generate your identity key. The method of securing it is up to you. In your example, a simple way would be to encrypt it with the 5 sequential keys. Or you could break the revocation key up into K parts with Shamir’s secret sharing algorithm.

This example assumes that you’re using existing Web of Trust PKI to manage your public keys: https://stackoverflow.com/questions/59664526/how-the-correct-way-to-revoke-gpg-on-key-server#62644875