You are right about that. In part, there was less abuse for three reasons (many others but these two are simple):
1. Less people/population. U.S. population just went to 300,000,000. It's up so significantly that even I can't help but notice. As in any good statistical comparison, one must take this into consideration - more people will always been more of any particular abberrant behavior.
2. Less disposable income back then - people didn't have nearly the amount of recreational cash that they do now, even though the Dems keep trying to say how bad-off we are now.
3. Morality was inculcated a lot more - while there will always be a criminal element and we all know about Al Capone, the great bootlegging criminals, and on and on, the fact is people back then were probably not as likely to just go start doing recreational drugs.
P.S. Don't start using the bit about the alcoholic women who'd go to those travelin' men selling all the "aids" since they did that out of ignorance, thinking it was medicine or herbal or good. They weren't taking a DRUG because they wanted some supernatural feelings, or feelings of euphoria.
P.S.S. In spite of our disagreements, you seem like a very nice person, so I respect you for that.