The success of localized pushes to legalize marijuana is a good sign. The failure on the federal level is not. Sadly the legalization push has largely been rationalized as "marijuana isn't that bad for you, it even has medical value" ; that same argument doesn't work very well in the other categories.
Rather, the legalization story needs to be switched to one where criminalization causes increased usage and death to abusers along with irreconcilable and inexcusable damage to bystanders.
Everyone with a rational mind knows what alcohol prohibition did. We need to break down the barriers erected by decades of government financed propaganda to move forward.
In Europe it does not only depend on the country but also on the city, which programs are available to addicts. The same goes for possession of minor quantities. Rules are highly confusing and it is usually safest to go by: "If you don't know the unspoken rules, try not to break the written ones."
The problem with drugs has changed though in recent years. The new generation of addicts are doing mostly research chemicals or regular pills like painkillers and such.
So in a sense some of the biggest drug dealers in the future will be pharma companies. When you hear how severe something like oxycodone withdrawal is compared to heroin withdrawal you understand that our societies drug problems have not peaked yet.