Uncle_Si - "Nearly every billionaire and millionaire in the free world at some point came from nothing."
JimiCliff - "Ummmmm...you can't possibly be serious."
The US has some of the worst social mobility around (comparable to feudal Pakistan, though still a bit better than communist China): the amount of money Americans have is strongly correlated to the amount of money that their parents had. Canada has much better social mobility.
Look at it this way: if your parents are billionaires, you'll have to be pretty incompetent not to be a multi-multi-millionaire (especially because most of the billionaires will set up a 'family office' to preserve wealth and make sure you don't piss it away). So if you look at a list of billionaires and millionaires, a significant number of them will have had very wealthy parents ... of course, with growing population over time, we will have had to have many new millionaires, because there weren't as millionaires in the past.