have been watching the financial markets for almost 50 years and i do not recall a single moment when there have not been more than one credible thinker with stock market crash predictions publicly asserted with remarkably similar rationals.
However infrequent, on at least three occasions they have been right to a point, except that civilization has survived all of them and the ensuing recovery has been stronger than ever in the stock market at least; meaning particular national economies have come and gone but the stock market will follow the money and doesn't really care about the US unemployment rate or which nations stimulate the growth.
For example, i have held Berkshire Hathaway stock since 1989 and have seen it lose 50% of its value three separate times, only to recover fabulously (silly me sold 2 of my 3 shares during one of those declines).
Nevertheless, if you bought at the 1929 peak, it would have taken you until 1954 to break even and that kind of thing or worse will happen again someday. But don't hold your breath.
But my view is to bet with the optimists on the general market all of the time and you will win 90% of the time. . If you bought $1,000 of stock at the market low in 1932, that would be worth $5,200,000 today.
The doomsdayers, like the poor, have always been with us. To bet against them is usually the right decision, though not always.