I think that what sometimes happen is that, by coincidence, a family does an intervention on their loved one, and that loved one goes into a recovery program and it sticks. So the family and anybody involved in that intervention thinks they had something to do with their loved one getting clean/sober. But the more I'm into this, the more i think that those times are just coincidence.
I also remember a story on Good Morning America (or some show like that) where a mom looked for her son in every drug house in some big town (New York City?) until she found him all strung out. He left with her, he went into rehab, and i guess it was a success story. If that's all it took to get my son clean/sober, i'd be driving around town right now looking for him instead of typing on this forum.
We're all here doing small interventions. Every time we tell our loved one that drugs/alcohol are their root problem, that's an intervention. Every day i get on here I read about some type of small intervention that somebody has done.
Like the poster above, I too thought that once my AS got somewhere (in his case, 3 months in boot-camp type jail) that the drugs would get out of his system and then, viola!, his cleaned-up brain would just take over and move him into permanent recovery. Not so. He was not ready to give it up. He still is not.