There a lots of case studies of lottery winners where they end up massively overspending their winnings and have a hard time returning to their old way of life, but can't maintain their temporary standard.

I think (but have no data) that that's less likely for people who made it big through business/startups. Although you certainly hear some stories about people who blow the money and have to go back to the grind.

Lost their house as they remortgaged to prop up the failed business venture of a sports bar. All those vacations to far of lands and gambling debts soon add up.