Xenophobia and nationalism sure don't help. We used to import the smartest most capable people from all across the world to develop and market their inventions and ideas and maybe even become rich in the process. Now, not so much.
But somehow China a country with even more Xenophobia and nationalism is catching up to us. And the U.S. used to have more Xenophobia and nationalism in the past and was also substantially more innovative.
Maybe the real problem is that the U.S. (all the way up to the top) has become anti-intellectual. We have completely dumbed down our culture so that children today want to be basketball players instead of astronauts. Our schools and government explicitly oppose meritocracy. There is just too much money in junk media and junk education that its never going to be fixed and instead we have to bring in more immigrants.
This is very unlike US style xenophobia where Murica number 1 and anything about foreigners sucks.
I know at least 3 genius-level people from Europe that refuse to go to the US, because they are white, and every single moment they see these "whitey are racist by just being white" they simply descend even more into their beliefs. Also, their humour would get them fired within a minute in the USA.
Something tells me the modern left (which generally isn't seen as xenophobic or nationalistic) would not take very kindly to the importation of Nazi rocket scientists in [current year].