Even just being really conservative on the ROI and going with 4.5% gains, if a person has $1,000,000 invested, that’s $45k a year to do nothing. The US median income is around $65k for reference. In lower cost of living places, a person can definitely live off of $45 a year assuming no debt. It won’t be the most comfortable life and it’s probably not worth retiring, but any other income could supplement for QoL upgrades, or further be invested, meaning more ROI, and compound interest, which means even more money.