I agree and think the QE from March 2020 only lead people to believe that stocks are safe assets. Then again if The Fed keeps printing, maybe it all just keeps going.
The QE from multiple times in previous decades should also work to help believe stocks are safe assets. And why wouldn’t it? As long as USA is relatively stable compared to other countries, and USD is desirable relative to other currencies, then I think it is reasonable to consider low cost broad market index funds to be inflation protected savings accounts on a 3+ year investment horizon.