I agree broadly with everything you've said but I think that you're unnecessarily implying/attempting to isolate it to a single cause, and I think it makes more sense as a variety of causes, all of which can contribute to what creates an addict:

* A lot of people who have broadly good lives get into trouble because their particular blend of biology and mental health makes them vulnerable to addictive behaviors, but others use those same drugs without issues

* People with poor life circumstances (and certain mental health conditions like ADHD) are more susceptible to addiction because they have rough lives and anything that gives you dopamine, be it exercise, casual sex or drugs has the potential to cause addiction, and people in those circumstances utilize behaviors for dopamine release more frequently and readily, and also have a stronger lack of dopamine when they stop

It's a very complex subject that's still developing, but one thing I think we can say for certain is that stigmatizing addicts and addiction and treating the people struggling with it as criminals doesn't solve anything. The criminal penalties for drug use and sale have never once helped anyone. What does seem to reliably help people struggling with addiction, any addiction, is support and safe places/drugs to use. And if GLP-1s can enhance that, I'm all for it.

And, it wouldn't hurt to change our society somewhat so we have fewer people on the bottom rungs of it, barely getting by due to whatever circumstance, whom are then less likely to get in trouble with drugs broadly. And to legalize drugs, because making them illegal doesn't do anything apart from inflate police departments' budgets, and push people who want drugs into dangerous situations, addiction being among them but not the only one.