So, while you may have remedied the supply side, killing off the cartels and giving the job of production over to corporations, you INCREASE the motivation of users and non users to use MORE.
Your analogy only works in terms of a general commodity market, where cost is the only downside. Drugs have their own inherent cost, and people recognize that. If cost was the primary deterrent to people doing drugs, I'd think you would see a substantial increase in drug use as you move up the economic scale, but you don't. Removing the profit from drugs stands to have a much greater affect on the associated crime rate than the rate of usage because there are much different motivating factors involved, respectively. - IMHO
However, that is not the main risk I fear from rampant drug use. I fear a community full of addicts.
It's much easier to turn down that fix when you must venture to some back alley, afraid for you life, spend more money, and risk getting a fake product, as opposed to walking into CVS pharmacy and grabbing one of the shelf.
Not the youth. Youth think that they are immortal.