Me, and a lot of my fellow non American co- workers in the US, always saw the USA as the land of opportunity:)
It’s possible the migrant hoards trying to enter the US feel the same way.
Is it good for the rich to get richer? I googled ‘income inequality vs growth’. There are mixed views on this in the economic world. It reminds me of the old joke that if you lined up 100 economists, they would all point in different directions. My impression is that the majority view is that income inequality has a negative correlation with growth. Maybe that’s just the way Google presents results.