> The blockchain is in particular trouble because it's decentralized. Every wallet holder would have to re-sign their transactions with quantum resistant key pairs. But this is unlikely to happen to a good number of wallets (eg Satoshi's wallet), meaning a bad actor will crack the wallets that haven't done this one by one. They will then accumulate a truly ridiculous sum of Bitcoin and devalue it for everyone else.

There will be some deadline after which old wallets just will not work (essentially destroyed). So Satoshi's wallet finally will vanish.