I take issue with the headline, and I didn't see any support for it in the article -- that people simply grow out of addiction. Treatment or not, we can call that process of reducing one's addictive behaviors growth, but I don't think you can find any addicts -- former or otherwise -- their families, or addiction treatment specialists, who would call that process simple.
Actually, speaking as a former addict, I would call it simple.
Damned hard, fucking painful, betimes hopeless, ..., but the most consistent memory from my early recovery was the simplicity of the process. There really was only one thing important: stay clean.
In my own case I aimed for staying clean for 2 years. And for those two years that was not "the most important thing", it was the only thing that mattered. Other factors helped too (supportive family was next most important), but I think I would not now be clean without the simplicity of that bright line rule of 2 years.
Rules may be simple, but adherence to them is not. For some, it may be impossible. Consider the first 2 rules of dating:
1. Be attractive
2. Don't be unattractive
The rule for winning is simply to score more points than the other team. Immortality is governed by the simple rule: Stay alive
None of these are simple processes, and it diminishes the discourse to treat them as such. I am thankful for your counterexample to my challenge, but I'm not convinced that, if asked sincerely about how you have managed your recovery from addiction, you could possibly sincerely respond: I simply grew out of it.
In that case, it is entirely the wrong expression to use. To simply grow out of something is to primarily yield to natural processes. Babies simply grow out of breast feeding. Toddlers simply grow out of putting random things in their mouths. Children simply grow out of name-calling and toy-hoarding. Adolescents simply grow out of feelings of invulnerability.
If an addict primarily yields to natural processes, he simply behaves in complete accordance with addiction.