These places still have pervasive drug use -- in fact, greater use than places without such penalties.
How much more severe can you be? Seems like immediate death doesn't deter drug use. Does that idea still make sense to you? Or perhaps in all of those places it just hasn't been done correctly yet?
Prohibition (which took a constitutional amendment, btw) had zero effect on alcohol use -- it actually probably encouraged it and the organized crime that came with it. We're still cleaning that mess up.
Anything you put into your body changes the way your body and brain operate -- including tap water. So everything is a drug. It's just a matter of degree. I remember hearing about kids in the 60s who smoked pot laughing about their parents who were way more hooked on valium. In fact, misuse of legal drugs is much more pervasive than illegal drug use. We live in a society where you pop a pill for everything.
Nope -- shooting folks doesn't make much sense: unless you just don't like people and want to get rid of a few. I'm a libertarian and opposed to constraints on what government tells me I can do with my own body, but I wouldn't want crack being sold out of vending machines either. It's a tough subject, and part of the problem is that people need to acknowledge that it's tough. Only through socialization and education can we have an intelligent discussion about where the limits are -- just like we did with alcohol. Quick fixes aren't going to work.