That is the standard line but i think there is a more logical and simpler explanation for why we became a "Power House,"
viz., we were the only major, mechanized nation left standing after two world wars twenty years apart!
The nations of western Europe, the British isles (who learned less well than the others) Scandanavia and Japan, essentially those countries with an educated populace, learned how childish, useless, destructive and stupid war is. They learned not to glorify it, but to recognize it as a disastrous result of human weakness and failure. We, on the other hand, never learned, and we go on celebrating war as if it were something to be proud of. We Americans have all become slaves to the industrial military complex and endless wars. Naturally, this will eventual destroy everything worthwhile about our country. We are already well on our way down that ignominious path.