Besides, the algorithm in question here is Shor's algorithm, it WILL be used to break some basic encryption. If Satoshi is dead, his coins will be hacked (they are old P2PK outputs). But there is no algorithm for breaking P2SH outputs (eg Native Segwit wallets). There could be, but Bitcoin has the ability to adapt if necessary. Bitcoin is not a static thing.
See also : https://www2.deloitte.com/nl/nl/pages/innovatie/artikelen/qu...
More importantly, quantum computers actually allow for something better than encryption. If you are having a secret conversation over the quantum internet, not only can no one listen in, BUT you will KNOW if they are listening. I read about this in David Deutsch's "Fabric of Reality," which I HIGHLY recommend and is freely available on archive.org https://archive.org/details/TheFabricOfReality/page/n1/mode/...
https://en.wikipedia.org/wiki/Quantum_cryptography#Mistrustf...