I think the wrinkle of "men (or maybe women) at a particular hingepoint had their personal foibles that shaped history" is valid. There were structural forces that led to WW2 but Churchill, Roosevelt, Stalin, Hitler et al being their particular personalities absolutely shaped how it unfolded.
From a UK perspective Churchill had a huge personal role in dragging the UK into the war against the initial public sentiment.
Not impossible if a few people at the top of the UK power structures had made different decisions then the UK could have stayed out of the war entirely, and the effect of that on the outcome would obviously have been drastic
