Pedantic, but. Families with $1m net worth are largely late-middle-aged (newly retired) salary workers with paid-off mortgages on their median-priced houses in suburban flyover country, plus ~40 years of 401k contributions and capital gains.

They drive Toyotas and fly economy for their 1-2 yearly vacations because that's what left when the 15% 401k contribution, mortgage on 3bd house, children's educations, and groceries are paid for.

Think teachers, bureaucrats, journalists (pre-internet), scientists, engineers, doctors, and lawyers, in roughly ascending order. What you'd call the upper middle class.

There are about 8 million millionaire households in the US as of 2016 [0].

Private jets are more a feature of the Fortune 500 CEO Davos-going class. $1 million in income maybe, very different from $1m net worth. It's not generally useful to conflate these wildly different wealth levels under the same terminology.

[0] https://en.wikipedia.org/wiki/Millionaire

Neither has much to do with being risk-takers, although you might be right that a higher arousal threshold desensitized them to risk. It may also be that people used to winning, on some level, expect to keep winning. Either way, we're not just talking about Fortune 500 C-levels here, plenty of people with loads of money and power did nothing to get it, and have no special qualities associated with that ability to get it.

They still often have bad outcomes.