The language I understand from the op is like simply saying if the previous strategy doesn't work looking for a better one and play them could be the best than just sticking the previous, that is why most people who do back-test still results back to what they had been facing due to either greed or fear of a market pressure and forces.
Yeah, I think his reply to my post makes it clearer. He also suggests that backtesting can help identify whether we're following our strategy closely or not, so it's not necessarily about creating new techniques but about figuring out habits and maintaining discipline too. I'm not sure how many people do backtesting regularly, but I'd assume the average joe who easily falls for emotional pressure probably doesn't do that. It takes some effort to stick with trading and improving your skills on that. CMIIW.