That's right. If someone nefariously accesses private keys, then so be it. Free market.

It already happens, it's called shotgun KYC. Go try to swap an OFAC sanctioned UTXO on Fixedfloat or another exchange.

Absolutely, let the coins that don’t merge be taken by quantum if it ever happens.

Wei’d just fork it

Quantum or no quantum: 2 things will happen: 1) There will be 'soft' forks (likely many from time to time) in the future that 'freeze' coins; and 2) should any of those 'soft' forks ever get anywhere close to becoming relevent, conventional bitcoin will hard fork away from that freezing of coins. ...

In that case there is literally nothing we can do to prepare. If/when a CRQC appears Bitcoin will simply fail as it becomes easy to steal and no longer represents a hard asset.