Quote from Murray Ruggiero:
Now here is the answer to your question. Why do people sell good systems ?
It's simple , you can make very good money selling systems and even if you are trading them , it will have no effect on your performance . This is because most traders are not disciplined enough to follow the rules long term. They will skip trades they consider risky which most often are the most profitable ones. This means that I can sell at least a given number of each system and not effect my trading returns. In addition I can make risk free this additional money from these sales.