You're failing to consider the fundamental point. The reason countries escalate is because they think it will bring victory. You can see the exact thing happeni

You're failing to consider the fundamental point. The reason countries escalate is because they think it will bring victory. You can see the exact thing happening in Ukraine today. There have been a million 'game changers'. What happens when those game changers fail to change the game? Further escalation. And the losing side will often delude themselves to this reality til long after it's become an inescapable truth. For instance during WW2 Nazi propaganda continued running and claiming imminent victory all the way up until the Fall of Berlin, even after Hitler's death - who was praised as having died in a glorious battle against Bolshevism. People who listened to the media only began to realize they had lost once the entire government had been dissolved. Nuclear annihilation will not come because of some desperate last ditch effort, but because of some politicians convincing themselves that they not only survive, but win, a nuclear conflict. And it's easier than ever to see that sort of mentality spreading in a world where narrative has become far more important than reality, at least to the idiots and octogenarians in charge.