What percent of public stocks are owned by funds in 401K accounts? Remember, price is driven by supply and demand. So long as there are more buyers than sellers the prices are going to keep rising. People blindly put money in funds every month. fund managers have to spread it around. Or in the case of index funds spread it by fixed formula. Sure there are good/bad companies and good/bad times, but so long as people keep pushing money in things will generally go up.

If CoViD had put white-collar people out of work, there wouldn't be any buyers and things would tank.