Sara rehabs work for people who are really ready to stop and stay stopped.
I know a ton of folks in AA that went to in some cases multiple rehabs and wound up drinking again, they all share that it was because they were not ready to do the work needed to stay sober after rehab.
All rehabs are geared towards putting a person on solid footing to continue to work a program of recovery after they leave rehab.
The majority of rehabs are of the 12 step variety, but not all of them.
When I was going through detox they told us repeatedly that if we wanted a chnce to stay clean and sober we needed to go to at least 90 AA meetings in 90 days and get a sponsor.
Every person I know who has gone through rehab and stayed sober continued to work a long term program of recovery. In a nut shell these folks say that rehab kept them sober long enough for the fog in thier heads to clear enough to where when they got out of rehab they were able to grasp and use a long term recovery program.
I get what they were saying, I was absolutely desperate to stay sober when I came out of detox, it took me a good month for the fog to clear in my head and for me to start really getting what I was hearing in meetings and what my sponsor and others were telling me.
I hope I at least partially answered your question. I heard some one here say that detox/rehab is kind of like a hospital, they get you just well enough to deliver one to a long term recovery program and them to stand a chance.