Over simplistic and would cost a fortune to police. It would just become another part of the war on drugs and we know that is a complete failure. Education is slow but it is working.
That is only because they are illegal. If legalized they would be no more of a problem than alcohol. Most people don't realize that the majority of junkies are well fed, well paid professionals. We only get to see the street people who are poor and malnourished. It is a media scam. Crack heads and crystal meth addicts are another animal altogether.
I think we should concern ourselves with the hard (street) drugs first and hang the pushers.