WW2 was probably the main ingredient, but without Mutually Assured Destruction, a common enemy in the Soviet Union, a booming economy as well as the lessons lea

WW2 was probably the main ingredient, but without Mutually Assured Destruction, a common enemy in the Soviet Union, a booming economy as well as the lessons learned in the 20's and 30's about not living beyond your means, the effect might have ended sooner. In other words, the 1945-2020 period required "luck" in a number of dimensions, and should be considered a fluke, not the norm.