I don't have a good answer.I think the trench warfare in WW1 vs the blitzkrieg tactics of the Nazis had greater shock value to civilians. Europe was flattened and it was the second world war in only 30 years. People were fed up with it everywhere.
My gut instinct leans towards the Marshall plan where we rebuilt Europe with an economy that worked for everyone instead of just a powerful few. Economic prosperity, interconnectedness and interdependence are major barriers to war.
I also think total war with the bombing of civilian populations helped break down class barriers in the civilian population. I remember reading about how the bliz on London hand everyone of all economic status hiding in the same bomb shelters. That shared experience made the wealthy more willing to pay for social safety net programs after the war.
Eisenhower played a pivotal role in picking up the torch and building on the social programs of the FDR and Truman administrations.