I have read other studies that reach the same conclusion, something that AA has known for quite a while. It certanly matches my experience and observations over many years in AA. I travel a lot, and I notice the guys that stay are the ones that get busy helping others. The rest are just a passing parade.
One which are the most important steps, step one was not enough to get me sober, and if I had skipped steps 2-9 I never would have been able to live steps 10, 11, 12, firstly because I would have got drunk, and secondly because I would have no understanding of the principles in 10,11 and 12 which are a summary of steps 1-9. All twelve steps were required for me to recover to that standard set in the big book.