Theory is for practice
Theory is good, but its main purpose is to give structure to the practice. This is the same principal behind. Theory is only good if it serves the goals of the practitioner.
Theory that does not serve the practitioner needs to be developed. Theory is for practice. That practice can then feedback to more developed theory. Good theory is experience plus reflection, and Music theory is just collected wisdom.
With this in mind, individuals can create their own music theory, like a.