Pretty simplistic thinking... It is the fog of drugs that saps motivation and the ability to hold a job, develop meaningful relationships, and take on one's rightful resonsibilities.
So if drugs are legal, and addicts being addicts - are you going to give them their drugs, money, housing, and healthcare so they do not commit crimes against persons or property? If not what are you solving? Are you willing to force birth control on them so we as a society need not be financially and morally responsible for their addiction born offspring (from cradle to grave). Do you feel it is morally acceptable to allow an addicts to procreate in the first place? I do not.
I tend to go the other way, if you manufacturer, distribute, sell, or profit from drugs - we have a trial, if you are found guilty - we shoot you in the head on national TV (so everyone gets the point of the excercise). If your an addict, we force birth control on you, we give you opportunities to help clean you up and get you back to being a productive member of society. Simply put, if your a dealer you're a parasite and need to be eliminated. If your an addict, you're abdicating your resonsibilities to the rest of us, so we'll make pragmatic decisions on your behalf until you're capable. And yes, I'd include docs that write obviously excessive scripts and their pill popping 'patients' as well. We're not gonna stop it all - when supply dries up, there will be folks who switch from meth to huffing, b/c that element will always exist. However, strong boarder control and extreme measures against the supply side and things would change radically within a generation. Infact, consider a single data subset - what happens to urban yutes if they are no longer warring over dope holes?