Depends entirely on when they plan to retire and life expectancy. Yields went negative during the crisis and with 10 years since, have only returned to 75 to 1

Depends entirely on when they plan to retire and life expectancy. Yields went negative during the crisis and with 10 years since, have only returned to 75 to 100 bps while real interest rates still lie below 0%. 4% withdrawal rate with zero earnings/dividend/asset appreciation isn't very sustainable even with "a couple million" depending upon where they live and how big of a cushion they want. Also - let's not forget that during a crisis, there can be a run on the bank which could lead to liquidity crisis where a bank might have it's position unwound in unfavorable terms where not everyone gets back what they put in. Even FDIC only insures 250k per account per bank, AFAIK.