That doesn't really account for the degree of inequality. Innate differences between human beings are the same in Sweden as they are in the USA, and yet Sweden has the lowest degree of inequality in the world (approximately), while the USA's numbers get listed alongside African dictatorships. The Swedes have just chosen to regularize away factors like family wealth or differences between school districts which create inequality but don't contribute to society positively in exchange. Americans are treating that statistical noise as meaningful information about "who deserves what" and conditioning on it.

The result is that Americans are just broadly doing worse, because our social system is irrational.