My theory is that capitalism wasn't quite as sophisticated and globalized yet, so an important project could collect literally the top 100 engineers in a field together. It's also back in a time when working for the government was a prestigious job that paid top of field.
Additionally the U.S. had probably better education and a stronger work culture. When only 5% of your country goes to college the classes can move really fast.
Additionally the U.S. had probably better education and a stronger work culture. When only 5% of your country goes to college the classes can move really fast.