Quote from justrading:
There is no profitable trading system that has been precisely as profitable, or even invariably profitable, ad infinitum.
Any extrapolation from that flawed premise is equally flawed.
Nothing could be further from the truth. I can show you trading systems that are still profitable 20 or 30 years after their creation, over 20 or 30 different financial instruments and with the same exact and simple trading rules.
The idea that a profitable trading system will cease to perform over time is absurd to the extreme!
Only losing systems cease to "perform", for the simple reason that they had no statistical edge to begin with.