Interesting question.
AA or not AA probably isnt that important a question. The important question is can the addict adopt a method of living built on rigorous honesty and do they have the desire to STOP drinking/using.
I did try to quit on my own. It didnt work very well for me: While I could avoid the bottle, I was more miserable than ever.
For this alcoholic, only the AA program gave me the boundaries to live the way I needed to in order to stay sober. Although AA doesnt have the market cornered on honesty and the desire for a "clean" life, it does offer the right tools for those of us who need and want them..