also an other thing: yes it would be in theory technically possible to change bitcoin to be highly quantum resistant and prevent panic and a catastrophic collapse of the market.
but it won't happen because:
1. there is no serious will or determination to go all the way necessary
2. it's brutally anti-scaling, would make the whole system degrade in UX
3. it would be contrary to bitcoin's most core principles (confiscation is a big no-no)
i guess you can't save something by undoing the best parts of it. it would not be the same thing. it would be something else.