Actually, the wealthy are moving away from the US not to it. Among the wealthy, there has emerged a "nomad" (or global) citizen. A "nomad" citizen changes their citizenship to a low tax country and then lives around the globe. They own residences in various nations and avoid living in any one of them long enough to qualify for taxes in that country. Other billionaires have relocated to the Caribbean, Singapore, or Qatar. The lose of those citizens does hurt a countries capital base since citizenship in their low tax countries generally requires them to maintain a substantial investment there.
I am open to new information if you have it. If you have a study that shows colonialism led to poverty in other countries, I would like to see it. I recently read one that Thomas Sowell produced that demonstrated standards of living are higher in ex British colonies than in countries that were never colonies. He argues that colonialism by countries like the Britain and the US actually resulted in the transfer of technology and expertise that gave these countries a "leg up" on their peers. But if you have better data, link me to it.
My problem with your statement is they simply don't jive with my life experience. I know so many immigrants that came here poor and have achieved the America dream. My wife is an Asian immigrant, as was my mother, and my daughter in law.
Each has realized success in America.
What is true is the "game keeps changing". Today, if you want to earn a good income, you must have skill that can't be outsourced and is in demand (like the first-generation Mexican tradesmen we contract with who earn $75/hour) or a college degree in a field in high demand. When my daughter graduates from advanced nursing school her estimated starting salary will be over $200K.
I do think many Americans more than immigrants are disappointed to find they just can't do any job and live well. The world doesn't exist to make people happy... as I always told my children, the world will pay you for what it wants, not what you want to do.
Lastly, a major source of immigrants are people fleeing countries where "the rule of law" has failed.
