This will be the largest loss of capital in human history, without any comparison.
"In a chart making the rounds on Wall Street, Ned Davis Research points out that the price-to-sales ratio for the median stock in the S&P 500 has risen to the highest value ever..."
I will summarize the attached article as:
BTFATH because TINA: "There Is No Alternative"
I performed another stock screen, this time across ALL companies > $25 million market cap (incl. ADR, CDN, excl. ETF, MLP, CEF):
Across all companies, 1694 or 30% are operating at a (combined) loss of -$198 billion, with a combined market cap of $3 trillion. Loss as a percentage of sales is -10%.