If no fork could solve it, in the worst case scenario it would just go to zero after a few hacks and no wealth would be transfered anymore.
How will it get to zero since not all addresses are vulnerable. People whose public keys aren't exposed are actually going to Hold. But I don't believe how people are projecting this quantum threat like a solutionless threat. I believe that a clear solution will suffice, if not a hard fork will solve the problem.
Some people are saying the quantum threat is 10-20 years ahead, others - 2 to 3 years, but who knows. For sure it will be the biggest transfer of digital wealth in human history.
Forget about the projections, it could be nearer than you think. And I am buying into the idea of BitGoba that banks will first fall victim before bitcoin. This is my first time hearing this and it is giving a resounding hope.