Serious flaw in your theory: take twelve kids from the same neighborhood with equal access to drugs, one obviously becomes an alcoholic at a young age, another doesn't like alcohol too much but smokes weed often, another gets into coke, one wonders off and becomes a heroin addict/prostitute, a few were more into shrooms; they all thought cigarettes were lame and bad for you so none of them smoked or drank much coffee. They ended up with different kinds of jobs; some died younger than others...that was life.
They did not all become addicts no matter what the Government did, and they definitely did not all become addicted to coke or any one drug in particular. Most never never got addicted to drugs yet maybe addicted to porn or the internet or gambling...the point is we all have a drug of choice. If some drugs are more evil than others, it's still your choice.
Reality proves that different people make different choices. The government has no right or ability to interfere with reality, it only makes things much worse when it selfishly tries to dominate/prohibit an aspect of existence that requires personal choice. This concept of choice does not apply to real crimes that harm OTHERS--not just self.