Predicting the future is obviously imperfect, but there's no particular reason to rule out investors realizing one day that stocks in all the "normal" companies

Predicting the future is obviously imperfect, but there's no particular reason to rule out investors realizing one day that stocks in all the "normal" companies are actually worth only half of what they were selling for the day before. It has been a long time since there was a major downturn in the market, but it is almost guaranteed that there will be another sooner or later.