Well, you could say prohibition didn't work, but you then also have to say legalization doesn't, either.
There are plenty of countries that have tried the legalization route, with terrible results - INCREASED crime, and many more addicts.
So, I can't be convinced that legalization is the way to go.
Medicinally, I agree that there should be appropriate use, but not to use drugs in the "legal" treatment of addicts, which hasn't worked in the past. And I think doctors are just as afraid of a patient or relative's lawsuit if they provide too many drugs to a patient, so "controls" are only half the problem.