I don't think it can. At least, in the upcoming few years, I think Quantum computers are still too expensive for someone to try such thing. I remember to watch a video quite some time ago and the video was explaining how hard it is to keep the computer running smoothly, how much energy it would spend and how would it cost, like per day, or something like that. The numbers were alarmingly high and the technology needed to keep the computer running was also large.
A part from that, I think there are already people working on Quantum resistant algorithms for when that time comes!
it would clearly be a profitable operation to run a qc, hacking few 1000s of btc/eth, then silently dump them to the sheep saying "quantum threat is decades away blablablabla". you won't see it coming even if you know that it's coming. And at first, it's clear that no individual or small organization will have access to such infrastructure, but some state sponsored actors or big tech corps (Google, IBM, Microsoft, etc) would
So, you think that not even the devs working on Bitcoin Core wouldn't see it coming in time of implementing Quantum resistance algorithms? I am sure they are aware and they are bright enough to see it coming. I mean, the technology must be developed, software must be developed and I don't believe that can be hidden from everyone up to a point that nobody will see it coming!