South Korea and Germany was a bombed out hellscape at the end of the Korean War and it’s rich now. Singapore and Hong Kong were also lacking in capital per capita. More importantly it’s been over 70 years. At the end of the war Silicon Valley was at best in embryo. Taiwan’s semiconductor industry did not exist.

“Historical reasons” is weaksauce if you can’t actually say what they are.

"Most" is an exaggeration. But many? Yes. In a survey of scientists from 16 countries (http://spectrum.ieee.org/at-work/tech-careers/the-global-bra... ), the US is the top destination from 13 of the 15 others and the #2 choice from the other two. If you are a Canadian scientist, there is a 16% chance (https://www.reddit.com/r/dataisbeautiful/comments/37lgxg/the... ) that you will move to the US. That's not "16% of all Canadian scientists that move out of the country move to the US". Let me repeat: *16% of all Canadian scientists move to the US.* They're also likely to be among the top Canadian scientists, too.

By comparison, 5% of all American scientists move to another country, of which 32% go to Canada, so about 1.6-1.7% total. Since the US has nine times more people, that means that in absolute numbers the 1.7% of American scientists is about equal to the 16% of Canadian scientists, but there is no reason to think that the 1.7% makes up the top tier of American scientists; why would the best move north of the border? In other words, the US is receiving the best of Canadian scientists in exchange for an equal number of its non-best.

Normalised for population, Switzerland blows the competition out of the water. The Swiss have twice the Nobel laureates per capita than the US, 2.5 times more than the Uk, seven times more than Germany.