Again with the quantum computers FUD. People just don't get tired of it it seems. If quantum computers can hack bitcoin, they can hack pretty much everything. Bank accounts, forum accounts, social media accounts, email accounts... Pretty much everything. The whole civilization would collapse.
That's why such thing will never happen.
If such risk appears on the horizon, bitcoin will update its algo, banks will use some other encryption algo that's quantum-proof...
If they try to hack people's accounts without telling us that they hacked SHA256, then they will rot in jail. There is no doubt about it.