Code proposes rules. People and institutions decide which code matters.
Why it matters
A quantum-response plan is ultimately a governance plan: new cryptography must be selected, implemented, activated and adopted.
Bitcoin's proposal path
BIP 3 states that BIPs are design documents and personal recommendations, not decrees from a decision body. Implementers, node operators, miners and the economy choose adoption through software and behavior.
Other governance models
Ethereum relies on proposal processes, client teams, validators and broad coordination. Other networks add foundations, councils, formal constitutions or token voting. Formal votes clarify some authority while sometimes concentrating it.
Quantum migration
A cryptographically relevant quantum computer would threaten exposed public-key schemes, not magically rewrite every hash. Networks would need new signature support, safe movement paths and policy for assets that do not migrate.
The hard decision
Protecting unmoved assets can conflict with property expectations; freezing or invalidating vulnerable outputs would be socially and technically contentious. Testing governance before urgency matters as much as selecting algorithms.