I was a binge/blackout drinker - had been drinking like that from age 15 to about age 26. What I wanted in life was to be a mom and wife. I got married and Mr. Big said - married people don't party. I agreed with that, so we both just quit.
Were we each others' support? I don't know. I do know I was pretty early in the progression of my disease. I was blacking out regularly, but was not yet drinking daily, or alone... though I was starting to drink more often during the week, and had an occassional "predrink" before going out... I drank that one alone.
I don't know if even 6 months later, my desire to be a mom and wife and my strong willed husband would have been enough "incentive" for me to be sober. I am glad I will never know.
Here's the kicker... 20 years later, I HAD to join a 12-step program to save my life. I got all obsessive and crazy over MY kids' addictions. Since then, I've learned that "alcoholism" is far bigger than just drinking... I have or had obsessions in many areas... work, pills, exercise, perfectionism... eating.
Imagine that... I didn't "fix" anything at all 20 years ago. But today, I do believe I am working on the "core" problem..... me.
So I guess my answer is "no" - lots of folks get sober without a program or social support. But in my mind, "true sobriety" and the serenity that comes with it DO require changes that are easier to implement through some sort of a program.
I wish you well.