Earlier quoted context omitted.
SO... BTC goes to zero?
I don’t see why bitcoin wouldn’t update its software in such a case. The majority of minors just need to agree. But why wouldn’t they if the alternative is going to zero?
No amount of software fixes can update this. In theory once an attack becomes feasible on the horizon they could update to post-quantum encryption and offer the ability to transfer from old-style addresses to new-style addresses, but this would be a herculean effort for everyone involved and would require all holders (not miners) to actively update their wallets. Basically infeasible.
Fortunately this will never actually happen. It's way more likely that ECDSA is broken by mundane means (better stochastic approaches most likely) than quantum computing being a factor.