I cannot answer for all immigrants, but in the case of Handsome Hombre*, his country of origin had very limited opportunities to work in his trade unless he was "connected". He was prevented from strengthening the economy of his native country because his identity was used to exclude him from "unions" and companies in cities.
In the United States, at least until very recently, employers did not care if you were black, white, brown, yellow or red. They did not care if you were Catholic, Protestant, Evangelical, Jew, Wican, Democrat, Republican or watched Sponge Bob reruns after work. They did not care if you were man, woman or other. They didn't care if you were tall, short, had six fingers or were legally blind. All they asked was "Can you do the job?**"
OK, it wasn't perfect that way. If you wanted to rise in management it helped if you graduated from the same University as the CEO and were a member of the same fraternity. But as a general rule, America was a meritocracy and that created opportunity that was denied elsewhere.
In American, all men who worked in the coal-mine were black and all men in the military bled red.
In India it MATTERS if you are Hindu, Muslim, Buddhist, Jainist, Sikh, Bengal or Tamil. Your caste matters and so does your province of origin.
In Syria or Iraq, it matters if you are Sunni, Shia, Druze, Christian or atheist.
In Central America, the city you were born in and your "family" matter.
Even in Ireland, it still matters if you are Catholic or Proddy.
The Tragedy
The tragedy is that powerful forces are working to turn the United States into India by making identity politics pervasive. "Jew", "Redneck", "Trailer park trash", "Bible thumper", "Native American", "Xenophobe", "Islamaphobe", "Trans-phobe", "Cis-male", blah, blah, blah...
Identity first, and then merit if it gets discussed at all.
The Legal System
You can ask "What made America unique?"
America's legal system evolved from English Common Law while the legal systems in most other countries are either much more corrupt or are unholy hybrids of native systems and English Common Law.
Given the corruptness of the courts in places like Haiti where one parcel of property can have six owners, businesses do not become corporations but remain either family-businesses or have extremely narrow hiring criteria. It is an adaptive response to a partisan, rapacious and corrupt legal system.
*Applause for Handsome Hombre. He was recently sworn-in as a US citizen along with about 200 other legal immigrants. He is very, very proud of his new country.
Among the proudest American citizens you will ever meet are first-generation citizens who actually lived in countries where the game was totally rigged against the common man. And that would be most of the countries in the world.
Incidentally, the Judge who presided over the swearing in was Chief Judge Hala Y. Jarbou, herself a naturalized US citizen who was a member of a persecuted, religious minority in her country of birth. Her speech to the assembly was inspiring.
**I supervised a quality inspector who was legally blind. He found as many defects as inspectors with "normal" eyesight and inspectors who were down-line of him did not catch any more "leakers" than for other inspectors. Even though he was legally-blind, he was not discriminated against.
He would even have been allowed to drive vehicles as long as he had a valid Michigan Driver's License. But since Michigan's S-o-S doesn't issue Driver's Licenses to blind people, that never became an issue.
