The US enjoyed a mix of resources (extensive rich soils and extraordinary mineral wealth) and climatic advantages that the others didn't, and ones moreover that were particularly valued in the 19th & 20th century - sprawling grain and grazing lands, sought-after cotton, coal, iron, oil - and an initially low settler population that enabled it to attain exceptionally high income levels early, propelling it into self-sustaining growth that in turn maintained a supply of work-ready immigrants whose children then benefited from early advances in educational provision.

Geopolitical superpower status didn't really come until 1945 with the Bomb and US troops on the Elbe and in Tokyo, but something like economic superpowerdom had been achieved earlier through a dynamic internal market and industrial leadership as early as the 1880s.