I think all efforts to contain marijuana are stupid. The gateway drug effect and the gang violence are functions of its illegality. Marijuana, like coffee, is only a problem if you become obsessed with it (like half the people who favor its legalization, thus making the work of legalization more difficult). I personally quit pot because of a thing that can only be described as "What's the point?" I think most people do and I think weed is a little less destructive than some prescription pain-killers and may help some people with other ailments like chronic nausea and glaucoma.

But other drugs... heroin and other opiates (including prescription ones misused), cocaine, heroin (worth mentioning again), methamphetamines, and debatably hallucinogens (I don't think so, but there are good arguments) are horrible. If the drug war removed pot from its scopes and focused on treatment and prevention of the use of these nasty drugs and alcohol when it's out of hand, it would actually save society in an economic sense more than its cost (invisible to most taxpayers in the form of jail, police, hospitalization, abuse, children on welfare, property damage, work-related injury, and a few other things). Actually it already does, but I personally think if they wasted less time on pot and used more resources on the nastier drugs it would be much more efficient. Treatment is in the long run cheaper and more productive than incarceration, but it requires willingness of the user and some social support (the guys who live alone are screwed unless they go to support groups continuously or make friends that aren't scum). Prevention would be even more efficient, but they need to find methods that actually work (if only there were some incentive for private companies to help out- the government will get there some day, but not anytime soon).
But in short, I agree with you on pot. Other drugs... I don't think you see the costs we really pay for them.