And it's still happening. America is, compared to other first world countries, not the easiest to immigrate to. So out of all immigrants, who would choose to go to America (appreciating that many immigrants don't have much choice)? The ones most aligned with America's opportunities, so people who want to be capitalists. If you value a chance at getting rich over stability and safety, come to America. If you want a strong social safety net and aren't willing to arm yourself against your neighbors, go somewhere else.