You've hit the nail on the head, and I think many people who have struggled with substance abuse disorders would agree: You can't fix whats inside by changing the outside... sure maybe changing external circumstance can help nudge you in the right direction, but it wont fix anything. Recovering drug addicts don't magically become functioning members of society just because they stopped using drugs... They do a lot of internal work, and find happiness within themselves, not within their surroundings or substances (or they go back to abusing drugs and die an addict).

If you are interested in any of this I highly recommend reading about the psychology of drug addiction more, because it is so very relevant to anyone and everyone at the end of the day (and very related to what you're speaking about). Even non-addicts can learn a lot about themselves and how to be happy, by learning how recovering drug addicts do it. If a formerly homeless heroin addict can find his way to happiness and 6 figure income, why wouldn't your average person not want to learn more about that journey for their own benefit? This is why a lot of recovering addicts wind up being more effective at life than the average person IF they managed to overcome addiction and stay sober. Overcoming addiction is like a master class in effectively living life, being happy, and overcoming anything. Its unfortunate that so few make it, but there's a lot be learned from it.