Many legendary value investors got destroyed in the 1998/1999 period as value got trashed and growth stocks (which many shorted) soared higher and higher. Think long airlines and commodity stocks, short tech stocks. Look up the charts and you'll feel their pain. It took a few years until 2001/2002 until they got redemption. The lesson here is value investors (just like any other investing/trading styles) don't always do well, there are markets where they face stiff headwinds, sometimes for multiple years in a row.
The short side was probably too big for him. I am glad that in 2017 I reduced my shorts to barely above minimum.
But on a risk adjusted basis, which is how the professionals keep score, he beats SPY and most mom and pop retails like me. Whereas I only care about the size of my account at the end of the year, don't care about and don't really understand risk adjusted basis.
"I know for sure he has a brain 10x better developed than mine. My admiration is sincere." Who said this is an IQ game? Certainly not Mr Buffett, who said to the contrary. How can a "genius" be short in such an uncommonly raging bull market as in 2017 ?