People get sober in a number of different ways. AA is not the only tool. It's one tool that works for a lot of people. Having said that, in my experience it is rare for somebody to find sobriety without working some kind of program be it AA, AVRT, Drug and Alcohol Counseling, their religion, or something.
Thanks so much for posting this. AA worked for me but I know people sober decades who aren't in AA. When I stopped drinking and in very bad shape 20 years ago I didn't know of any alternative. I'm an agnostic and have no concept of a Christian god so I work secular steps. No problem in New York but outside many alcoholics are strident.
And you're right: especially in the beginning some sort of program is necessary. One addiction physician said it isn't one size fits all. It's frequently a combination of things (medication, cognitive therapy and support program). There's a difference between an alcoholic/addict who drank a few years and is young and someone who drank for decades. And, some of us are sicker than others.