alt Hacker NewsAIUI, the scientists achieved a self-sustaining nuclear chain reaction around 1943. That was the hard part, not even a small bomb yet, but a bomb just needed more fuel and scale.
Fault tolerance is the hard part for QC, once it's achieved, the difference between factoring 35 and RSA-2048 is an engineering challenge, not an impossibility.
Fault tolerance is a hard problem, assembling qubits for simultaneous gate operations is another hard problem. There are several dozen others.
It is exceptionally unlikely CRQC will be achieved in our lifetimes, if ever. The closer example is economically-viable fusion power production, which today has better odds than CRQC but remains solidly in the "maybe" zone after decades of global investment. Even though fusion weapons had been achieved half a century beforehand.
The bombs were actually relatively easy problems, in the scheme of things.
It is never wise to listen to people who's jobs and funding are connected to the development of a technology on when that technology will arrive. The answer is always "soon".