Stretching the analogy from the original commenter, the code is “in production “. It is already running, it is the conscious part of you. Reading all the self help books in the world will only reinforce the things that the system already believes and reject uncomfortable things. As for introspection, often by the time people get therapy, the processor load is already high enough that there is little room for introspection. A therapist is a trained debugger, and can help you get out of your own head and see things more “objectively”.

Also knowing is different from doing. What’s stopping you learning karate or bjj from books or even videos? You already have the hardware for it. But you need to learn new patterns, and a coach can often get you there more effectively. Also having a sparring partner is a good way to break old patterns and build new ones. Now replace karate with mental models/peace of mind etc, except now your system is not performing optimally by this point.