[ttoinou]

  - Nuclear weapons - not inevitable. Uranium separation is so hard that somebody had to spend billions to get it to work at all. It wasn't clear that fission could be made to work.

The mainstream explanation is that the threat that someone else could be researching and investing is enough of push to try yourself

  Looking at the issue in this way moves it from rhetoric to reality.

I would say moving from rhetoric to a simple 3 parameters model ("how many people can research this, how much resources it takes, how useful the promised result it")