What made the U.S. a number of countries worldwide since gaining independence from the British Empire?
If you do argues that we are not the greatest answer that please.
WW2 kick our economy in depression and production, it has also spurred technological development, which for the first time actually turned into a world power. After WW2, most countries have been destroyed, except ours, I think in the late 40s and early 50s, we have effectively controlled 52% of trade worldwide. It was the Cold War that pushed us from a world power in what is now called a "super power ". The U.S. economy and technology has declined in relative terms since then, but these two events have been major development United States. This has pushed the U.S. economic and technological development in any case.