Time has passed, and we still haven't blown up our world, despite a close call or two.

I can't help but wonder about anthropic effects here. It might be the case that nuclear-armed species annihilate themselves with high probability (say 50% per decade), but of course, all surviving observers live on planets where it hasn't happened through sheer chance.

(Though on the other hand, if an all-out nuclear war is survivable for a species like ours, then this line of thought wouldn't work.)