That doesn't happen because inflation and growth works to push the market up more years than not. Very rarely does the US stock market go down more than one year in a row. Not saying it wont happen now, but by your definition bear markets have hardly ever happened in the US markets.
More accurate than not. Just look at the lonnnng term chart of the Dow. Just because the markets are usually bullish (for a host of reasons) doesn't mean bear markets are not at the least painful and the worst, devastating. There's a LOT more pain and anguish to bear markets than just being "down 20%".
It's because there has been no follow thru selling yet. It remains to be seen whether we are in a bear market yet. I deal with facts.