Everyone focuses on whether quantum will break the encryption but both banks and decentralized networks are in the same boat, they both have to upgrade fast enough. And hardware keeps doubling every few years so any encryption we pick today will eventually be crackable anyway. The real question is whether you can design systems where the data is useless even if someone decrypts it. If the information is split up and scattered in a way where cracking one piece doesn't give you anything meaningful you don't have to win the encryption arms race, you just have to make it not worth the effort.