I have no idea why you’re being down voted. You’re absolutely right. You can’t live on back interest from $1M, so you have to invest it, and while some years you’ll make more than 10% average invested in the stock market, over 10 years you’ll average 8% because some years you’ll not only make no returns but you’ll lose some of your investment. Which means if you’re living off those returns, some years you’ll have to eat into those investments, slowly eating down the money you have making money for you. You’re paying taxes on those returns, and if you’re living off them, they’re considered short term investments and you pay a higher tax rate - because you pay taxes on returns on your investments.
Rich people get richer because they have other income and can leave the money and the returns untouched; they aren’t living on the returns until they have far more money invested than $1M.