Relative position also matters quite a bit. In Denmark, you can be born on the lower end of society, and end up as one of the country's elites, with greater probability than is the case in the US. I take this as the "Horatio Alger" myth: you are born to a dock worker, and end up President of the USA, or CEO of a Big Company, a unique trajectory only possible in America. But you are actually more likely to make this dockworker-to-PM or dockworker-to-CEO transition in Denmark, contrary to the myth! Put differently, who constitutes the elite in Denmark is less determined by parentage, whereas the American political/economic/cultural elite is more heredity-determined, because the differences from birth are too large to overcome. I think this question of which stratum of the previous generation's families this generation's CEOs/etc. come from has significant implications for society: if it's only from last generation's top-20%, this produces a multi-generational elite, which is generally bad. It could well be that one way to combat the emergence of a multi-generational elite is simply to reduce income inequality.
Steve Jobs
Sergey Brin
Jeff Bezos
David Koch
Michael Dell
Bill Clinton
http://exiledonline.com/a-peoples-history-of-koch-industries...
(Your list) * (20000000 other people)
"kaufkraftindex je einwohner" -> "purchasing power per capita"
One very common argument I hear from Americans is something like this: it's true that (some of) Europe has lower income inequality than the US. However, Europe's inequality is more entrenched and hereditary, and therefore actually worse than America's in social effects, even though in magnitude it seems less bad. The difference between wealthier and poorer parts of society, this argument goes, is higher in America, but this is not as harmful because the divergence is just based on what you make of yourself and changes generation to generation, rather than being based on rigid notions of class or heredity like in Europe and persisting across generations. So the European rich man might only be 10x as rich as the poor man, while the American one is 100x, but the European has this 10x difference predestined from birth, whereas the American's 100x arises only during life.
This study seems to show that particular narrative doesn't quite go through: the U.S. has a larger class divide and it persists across generations more than Europe's smaller class divide does. The second part may well be redundant, as you point out (it might only persist more because it's larger), but that doesn't necessarily make the problem any less bad.