Culture is a thing, different people in different cultures value different things. Even within small countries there are major differences between villages not 2 miles from each other. And don't forget that a lot of groups historically where low wage workers to begin with, so to make any meaningful comparison you should compare them only to people from similar standings in society from the moment they have arrived. As an example, you can't compare a child born to someone who sought asylum in a country to a native born with well off parents. The second generation child will not have the amount connections that the native child has, simply because of the means of the parents and because they have roots there. It isn't because the second generation child is of a different culture or anything like that, but rather because they have less connections and money.
Not really, greed isn't really something that helped us surviving, we are a herd animal, or a pack animal, depends on how you define humans. The one thing that made us so successful is that we can work together and share. And greed and violence aren't mechanisms that make you think in a certain way, like it does with us discriminating.