As I said, yes but only to a lesser extent. Unless you think enforcement has literally zero effect on people's tendency to use drugs of any sort?
Excellent, it's too late to do anything about it. But that does rather imply that you would do something about it if you could. And in the case of marijuana, there is still something you can do about it, and that is to keep it illegal. By your own admission(and I would agree), it's too late to criminalise alcohol and tobacco. But the same cannot be said of marijuana.