The author is talking about a definition of wealth in the top quintile, 20%, or top 80 million of Americans. In some other figures he talked about upper class in pew's research, which is double the national median income. Households in that income bracket earns a whopping $187,872 per year, and have $848,000 in wealth. Why are people talking about founders and the extremely wealthy in context of those numbers?

Most of those people are regular people with regular incomes with good saving habit, and/or got lucky because the house they bought 30 years ago happen to be in a boom area.