CZ suggested when discussing the threat of quantum attacks: The Bitcoin community could consider a quantum upgrade in the future, giving old address holders 6-12 months to migrate their coins to new quantum-secure addresses. If they don’t migrate (including Satoshi’s coins), these coins could be frozen under the new protocol to prevent hackers from stealing them. This would reduce the BTC supply on the new chain to 20 million coins. Everyone’s eyeing Satoshi’s coins—human greed is far scarier than quantum attacks.