Anecdotally, it seems that practically every billionaire in the US comes from an upbringing in the comfortable middle class. This is basically what we'd expect

Anecdotally, it seems that practically every billionaire in the US comes from an upbringing in the comfortable middle class. This is basically what we'd expect, given that: a) Folks who become rich are generally pretty darn smart. b) People who are smart generally have smart parents. c) The vast majority of smart people are in the comfortable middle class. (Not the poor, since they're smart enough not to be poor, but not the very rich, because statistically there ain't that many of 'em) Therefore, if you're rich you probably had comfortably middle class parents.