Further, the premise of deterrence is shaken when you consider the post 9/11 Pakistan example. The US threatened to 'bomb Pakistan back into the Stone Age' [1] if they did not comply with US demands in relation to post 9/11 military action. The US was not deterred by Pakistan having nuclear weapons.
It can also do the opposite of increase dictatorship stability. It increases the value of taking control of the country if you're an internal revolutionary group. If you're one of those groups and you topple a Gaddafi or Bashar al-Assad, or the House of Saud, once they have nukes, you become drastically more powerful on the world stage. It's a very large incentive to try to overthrow them. It's potentially a giant lever of power and blackmail.
[1] "President Pervez Musharraf of Pakistan said yesterday that after the Sept. 11, 2001, attacks the United States threatened to bomb his country if it did not cooperate with the American campaign against the Taliban in Afghanistan."
"General Musharraf said the intelligence director had told him that Mr. Armitage had said: “‘Be prepared to be bombed. Be prepared to go back to the Stone Age.’"
https://www.nytimes.com/2006/09/22/world/asia/22pakistan.htm...
Because they were not there for resource. Iraq would have been another story: getting oil from a radiation scorched area is not fun.
And if you know enough about technology, there's no system where the accidents never happen. We were just lucky up to now, but it doesn't prove anything. See Nassim Taleb's turkey example:
https://www.businessinsider.com.au/nassim-talebs-black-swan-...
"“A turkey is fed for a thousand days by a butcher, every day is a confirmation to his team of analysts that butchers love turkeys” with statistical confidence increasing daily. “The butcher will continue to feed the turkey until a few days before Thanksgiving Day. And then comes the time when it’s not really a good idea to be a turkey. Being surprised by the butcher, the turkey reviews his beliefs when his confidence in the assertion that the butcher loves Turkeys is at its peak and the Turkey’s life is “very serene” and mildly predictable. This example is based on the adaptation of a metaphor created by Bertrand Russell. From the Turkey’s story, we can also identify the source of all prejudicial errors: confusing the absence of evidence (damages) with the evidence of its absence“"
The treaties about the control between the countries already existed, allowing one country to control another claims and that did reduce the amount of the weapons. One can see that they didn't dismantle enough however to reduce the threat enough. However:
August 2019: "Donald Trump officially terminated a longstanding U.S. nuclear treaty with Russia, potentially signaling the beginning of the end of the arms control architecture that has regulated nuclear weapons since the Cold War."
The sane policy would move in another direction.
https://thebulletin.org/2019/08/the-inf-treaty-is-done-but-l...
https://www.theguardian.com/world/2019/jan/24/doomsday-clock...
"We are like passengers on the Titanic, ignoring the iceberg ahead" ... "the political response is alarming. It’s akin to sleepwalking"
"You go first!"
It will never ever happen.
The potential for a nuclear holocaust still very much exist today, our fingers are poised over the button. It’s a catastrophe waiting to happen.