It's not american culture, its Narcissism. I'm gonna keep repeating it, because that is the secret sauce people keep over looking. It doesn't have to be someone from another country, someone who moves to another state will usually be more active in trying to become "successful" then the people who are from there. The issue is what do you call successful? Some are happy with money in the bank, eating good, having clothes, and shelter. Others want prestige, and massive wealth. The latter is what you usually find with people who leave their home to venture out, and they come from a place of lacking. This is how the mind works. notice when you are hungry, as soon as you can eat you go crazy and eat everything in sight, but when you aren't extremely hungry you take what you want, and you are satisfied. It's the same thing when someone comes from a place of lack then gets opportunity. The problem is if this way of living isn't controlled it can cause mental illness, including narcissism. To some its normal, but for healthy minded people, its insanity. It depends on your environment. Why do you think whites were so crazy on conquering the world? They came from a place that was fukked up, once they saw all the other lands that were fruitful, they lost their minds. The people who lived in these lands didn't feel a need to own everything, they had so much that greed, and ownership, wasn't even a thought!
Also, there is a higher percentage of Africans immigrants who live in poverty(19%), and they don't get paid properly for their educational attainment(69% have college degrees when coming here). Whites who don't have degrees get more then they do! shyt is fukked up, but unless people stop feeding their narcissism, and expose the foulness, nothing will change. This is why its important to keep a humble character, if not your enemy will use your ego to hurt you.