Of course, there may be deep and prolonged bear markets. However, central banks keep producing new money that would eventually push the price of stocks and bonds up. Yes, you may lament about moral hazard, but if you invest in the stock market, you win in the end. You keep winning.
Naive investors will see the value of their investments growing over time, even though bear markets may hamper the growth from time to time (see the green line below). A permabear, however, will end up embittered and losing money, even if he may have been be considered as a hero during the crisis. See the blue area below—the growth (and decline) of the $10,000 invested into Hussman Strategic Growth 10 years ago: