There are many extremely intelligent and financially sophisticated people, oftentimes finance professionals, who are still incapable of executing a plan properly. The most common reason for the "failure to execute" shortcoming is the emotional inability to go against the market. Commonly known as "Commitment Paralysis."
I wrote a StockFetcher filter, FINDING THE NEXT NTRI - Double Verison, that does that... very profitable.
Whenever I have a HUGE trade on, I visualize executing my exit. For example: If the price hits xx.99, I see myself pressing SELL. If the price hits xx.95, I see myself pressing SELL. etc... I visualize all the scenarios that I want to execute so when the time comes I pull the trigger. No thought. No hesitation. Pure reaction. And don't forget to visualize what you will do if you get a PARTIAL FILL or your order is skipped over!! MAY ALL YOUR FILLS BE COMPLETE.
If it is "FREE" then many perceive there's a "catch". People value what they pay for. There is so much free stuff on the net, yet people pay for information and trading code they could get for free, if only they looked for it. Those are some of the reasons people charge for their products and services.