Good question Pink...could it be money?
The "treatment" industry has made a fortune off of the 12 step approach. You can find a treatment center for just about any addiction...most using the 12 step approach. How are their recovery rates? No better that aa I would guess.
BTW Bill didn't have all the answers....addiction was around long before the bb and I venture to say will be long after it stops being the final word on the subject.