While there have been conflicts and violence, and the period of time following the development of nuclear weapons has been too short to say definitively, we've had unprecedented levels of peace since the development of nuclear weapons.

One has to come to the conclusion that it was inevitable. The simplest fission bomb is trivially simple to describe once the physics are known.

Not trivial to make without the resources of a major industrial nation, but the actual simplest mechanism is essentially just sufficiently purifying two lumps of a metal of sufficient size and quickly smashing them together.

You don’t get modern technology, say the transistor, without nuclear inevitability.

Hard to say, nuclear weapons have also prevented WWIII so far.

It's hard to imagine some country wouldn't have pulled it off. The physics were beginning to be understood (and it's worth remembering: until the first test detonations, the actual power of the weapons was not well understood. Granted, once it was understood, the country that developed them did choose to deploy them on a civilian populace...).

Not disagreeing with you, but I'm sure we can all agree nukes in the hands of Nazi Germany would have been an unmitigated disaster.