fluterbus on Nostr: ahh I think I heard this before. Then both forks would run simultaneously, so if the ...

ahh I think I heard this before. Then both forks would run simultaneously, so if the qc get to break sha-256 then the market (users+miners) should migrate to the sha-512 chain? and if so, isn't there a weakness to 51% attack period in the new chain bc the hashrate is so low?