Much of WWII was based on overwhelming cheap (and field reparable) machinery backed by industrial capacity while the Germans had the finely crafted equipment.

Somewhere in the next decades, the US has switched to being the finely crafted military equipment.

My armchair historian says that the technology innovations are done during peacetime while treaties limit the size of the forces. ( https://en.wikipedia.org/wiki/Washington_Naval_Treaty https://en.wikipedia.org/wiki/Treaty_on_Conventional_Armed_F... ) while the inventions happen during the war itself. This in turn means that much of the technology innovation is focused on fighting the last war.

With the Pax Americana ( https://en.wikipedia.org/wiki/Pax_Americana ) and various policies (could the military industrial complex have survived the Last Supper? https://en.wikipedia.org/wiki/Last_Supper_(defense_industry) ... and how has that contributed to current budgets and projects?) the United States has produced cutting edge military equipment. We've certainly left that period.