The people who will first have access to sufficient quantum computing power (to hack bitcoin) will be the entities that created it, e.g. university research departments, government labs, major technology corporations, etc. These people will likely not use the technology for nefarious purposes, and they will have access to the technology long before the bad actors will.
How does this help the scenario thought by OP? It would be enough for such an University or Laboratory to publicly declare a win against Bitcoin and then to see all the weak Addresses emptied out. This alone would cause enough chaos for the progress of Bitcoin to be set back years in my opinion. Only because they are not Criminals themselves it does not mean they can not cause abrupt chaos for Bitcoin if and when they have the 'key' to what is thought Satoshi initially held.
PrivacyG is very correct and having such university or laboratory, public entities at the control of bitcoin development for whatever reason have already defeated the nature of bitcoin which is decentralization that alone have made bitcoin more centralised since few known entities control all bitcoin in whichever wallet it been stored, so this still leads to control and let st of freedom and that is criminal idea already.
It's far from that and bitcoin is decentralised enough, to beat any possible attempt for it to be controlled by a known entity or criminals since hacking bitcoin is almost impossible athe moment.