70 years is not a useful timeframe for analysis of human warfare. Historically speaking a 70 year peace could be considered brief. Recall that empires have lasted thousands of years, city states have warred on and off for centuries, warlords have emerged with a cadence measured in centuries and great conquests on a cadence of thousands of years.
70 years is a blip. Compare that to the 6 known close calls where all-out nuclear war was narrowly averted and we’re not looking great. (What is that about once a decade?)
I’d say there’s a 50/50 chance I’ll see a nuclear war in my lifetime. And if it gets out of hand billions of people will die.
I’m not sure the invention of nuclear weapons was a net positive for the world.
All it tells me (just personally) is that the threat of being nuked (and especially being nuked in retaliation) is an effective deterrent since 1945. Not perfect of course, but it’s prevented larger conflicts than we have seen.