Some people don't get better because they don't want to go through the struggle badly enough. Trying to fight the craving to drink one day at a time and suddenly having to face life on life's terms is difficult for someone who has been zoned out in laa-laa land for a long time.
The last time AH was in a 28-day rehab facility, I met with one of his counselors after he'd been in there two weeks and told her he wasn't going to make it. I realized that he could play the game well and say what was expected of him, but there were far too many underlying problems/issues. He wasn't willing to face his own problems, preferring to avoid life in general by getting drunk; thus, he never maintained sobriety for more than a few weeks.
Rehab #3 was "the charm" for me. I just worked on getting out of his way so he could work on drinking himself to death. Sad, but true.