In the ancient world, Salt was as valuable as gold. Wood, Coal etc. Human brains are no different. Hunter and Gatherers, Agrarian, Industrial, Post industrial economies each have different requirements to survive. Technology since its inception , through irrigation, screw etc has reduced the need for brawn and increased the need for brain.
Today we've arrived at a breaking point, England, Germany, Spain, Australia will tell you the same, immigration policies of the 20th century aren't working anymore, and are more detrimental than anything else.
Today we see the negative effects and positive ones. While low skill masses provide tax bonus , their small purchasing power and their outdated cultures also drain tax coffers. Lower standard of living, their lack of value in education also lowers the future of their own children, lower wages, drain public services while it takes multiple generations for them to adapt to Western Culture.
Someone who is already skilled/educated or resourceful will have a much shorter time to adapt to Western Culture regardless of which one it may be. This increases growth while stopping the draining on public resources. The example is to use Detroit as a template for immigration but opposite. Make it easier for individuals from other countries with skills, degrees or money to come into the UNited States while make it harder for those who do not have those requirements, unless they come through a Student Visa.
At the end of their bachelor's reward them with a green card, to further push the adaptation to the native culture.
We should be accepting individuals for their brains, not for their capacity to multiply like humanity is facing extinction. Competing with China on quantity is a fool's gambit, our trade card today is quality, technology. See how vegetables are farmed in California, and how potatoes/wheat are farmed in the Midwest. I come from Colombia and its embarassing watching a US state using farming practices of 3rd world countries, when we already have technology to mechanize the process and thus make fruits and vegetables as affordable as potatoes and wheat.