And not just rich: rich-rich.
See CNNs list of The Richest Americans in History.
And now note Cafe Hayek’s comment:
Of them, only one – Stephen Van Rensselaer (#6 on the list) – inherited a large fortune. All of the others began life either modestly or, like #1, J.D. Rockefeller, began life downright, hard-scrabble poor.