There is a certain total of income for salary available in a country; e.g, the US is spending about 44% of GDP on salaries/compensation[1]. The difference in income for software engineers is partially (and possible mainly) because the US is very income-inequal - ie, because there are more poor people to prop you up. If you look at income inequality before taxes and transfers[2], the US is the most income-inequal of any of the OECD countries. If you look at it after taxes and transfers[3], Chile, Turkey and Mexico manage to do worse.