Look how magnificently such a strategy worked for drugs.
NSO style products are used by one entity against another entity. As a result enforcement is a fundamentally different sort of problem. There is a complainant.
This is such a shallow comparison, which seems to come up with every discussion around criminalization. Law enforcement isn’t 100% effective but that doesn’t mean every criminalized activity should be legal.
Also, unlike software vulnerabilities, nuclear weapons don't have a half-life counted in weeks.
The Manhattan project consumed 10% of the total US energy output in the mid 1940s. And obviously uranium is hard to come across.