Society is really hard to change. We figured drug use was “just” a social problem, and it’s obvious how to solve social problems, so we gave kids nice little lessons in school about how you should Just Say No. There were advertisements in sports and video games about how Winners Don’t Do Drugs. And just in case that didn’t work, the cherry on the social engineering sundae was putting all the drug users in jail, where they would have a lot of time to think about what they’d done and be so moved by the prospect of further punishment that they would come clean.
And that is why, even to this day, nobody uses drugs.
On the other hand, biology is gratifyingly easy to change. Sometimes it’s just giving people more iron supplements. But the best example is lead. Banning lead was probably kind of controversial at the time, but in the end some refineries probably had to change their refining process and some gas stations had to put up “UNLEADED” signs and then we were done. And crime dropped like fifty percent in a couple of decades – including many forms of drug abuse.