Very few people saw this coming. When you think about it, very few people saw the 2008 sub-prime crash coming either. Very few people saw the dot com crash coming either. Very few people saw the 1929 crash coming either.
My financial advisor is Jeffrey Gundlach who stated that 2019 should be an "asset preservation year". Since the yield curve inverted and I did not believe a bull market last forever, I re-allocated my 60/40 portfolio to 100% treasury bonds in the summer of 2019. I understood how treasuries bonds work so this is now my best bear market ever.
I also believe that investing in the stock market is similar to gambling but better odds are involved. I like to quote Kenny Rogers (RIP) in his song the Gambler:
You have to know when to hold them,
know when to fold them,
know when to walk away.
If investors know when to walk away, this can make a HUGE difference in your portfolio. Since I was retired and approaching 70, it was my personal financial objective to avoid the next bear market because I did not have time to wait for the recovery. I was looking for signs to walk away, found them, and made the decision to reallocate to 100% treasuries in 2019 after the yield curve inverted.
IMO, equity risks are high at the end of a historical bull market but the equity risks are low after a crash. I am now buying equities.