Yeah I've seen the destruction that comes from removing legal/social consequences for drug abuse. Neglected and abandoned children is by far the most tragic. The community of non-addicts bears the responsibility for cleaning up the destruction, the addicts themselves cannot. That's the nature of addiction. To be clear I'm talking about the hard drugs; opiates, cocaine, meth.

I believe addiction is a disease, but treatment is elusive. Some have no desire to stop. There are also frequently other mental or emotional problems. Just feeding addiction's most obvious symptom (by continual drug use) does nothing - see this article.

I doubt whether there will ever be a neat and tidy "solution". Eventually the healthy part of society will have enough and some action will be taken, like prohibition or war on drugs, etc. Then it will wax the other way again.