There's this, but let's not forget that the S&P 500 is up about 40% relative to its pre-pandemic peak, so retirement accounts have been growing really fast. Staying home suddenly became an option for many.

There were already concerns about boomer retirements. Add a pandemic most dangerous to older people, lack of concern for worker safety, and massive increases in retirement accounts, and you have a lot of people that can and do stay home.