One big problem is that while the US has finally wrapped its brain around the fact that incarceration doesn't fix drug addiction, we have mistakenly fallen into the belief that treatment does. But even the absolute gold-standard treatment program (residential group and individual therapy with chemical assistance where appropriate) has about a 25% success rate (meaning still clean after 5 years).

Literally no matter what we do we are going to have a large number of people who have drugged their way out of society and will not be able to come back. And we need to figure out what to do about that.