This is philosophical nonsense. We need practical solutions, not whatever the heck this is you wrote.

This can be easily proven on Bitcoin if you SHA256 your key before OP_CHECKSIGVERIFY. Then you sign for the hash of the public key, unlocking that script. That's the best proof we can have, and we might not get the courtesy because quantum computing isn't sovereign computing.

The BIPs are optional. P2QRH addresses are optional, even after activation. They don't lock you into something you can't exit (so long as you have the keys). What's the harm in being proactive about such a conservative security upgrade?