The USA had large natural resources such as coal, iron, oil and plenty of fertile land. Therefore they did not need to import much as they could sell lots off products to the rapidly growing American population.

Higher steel production is a good idication of a country’s strength and military power. To give you some idea of how well the USA was doing here is a the steel production of the top nations in the world at the time.

STEEL PRODUCTION (in millions of tons)

1913

USA 32
Britain 8
Germany 18
France 5

1920

USA 42
Britain 9
Germany 8
France 5