Quote from fkeane:
My 2 cents on the common themes causing the great ones to fall are 1) hubris and 2) ever changing cycles (a Neiferhoffer expression) i.e. what seems to work consistently suddenly stops working - something in the market changes.
ironically, having a method with bigger volatility swings and drawdowns can actually indicate a higher degree of long term fitness rather than lower.
there are billion dollar trend following firms that have been around for 20+ years because their strategies are "mitten fit" - loose enough and robust enough to survive the vast expanse of market conditions without changing much of anything. They accept high account volatility in exchange for high survivability.
the smoother someone's equity curve is, the more likelihood that their trading strategy is glove fit rather than mitten fit- meaning they have figured out a way to exploit a temporary aberration.
the tradeoff for the smooth curve / glove fit is that it won't last - too optimized to current conditions, whereas the robust mitten guys will be able to keep on swingin' as long as they don't hit a drawdown that kills them.
then you have guys like PTJ who are so loaded with alpha that all the rules for mere mortals go out the window. To have nearly two decades of all positive returns and yet still be able to rack up gains of 100-200% under the right conditions... awe inspiring.