I don't get the argument you are attempting to make here. If its that prohibition drives people to more potent substances, I'll point out that legal marijuana has become insanely potent.

Also, cheap vodkas are cheaper and more accessible to people who abuse alcohol, not mention far far more palatable. And that's exactly what alcoholics tend toward.

Lots of factors play into which drugs people consume, and prohibition plays a role.

You jest, but this actually happened during the era of alcohol prohibition: hard liquor went from around 40% of US alcohol sales to 75%. Bootleggers preferred liquor because the profit margin was higher and because it was easier to conceal. After prohibition ended, the proportion of hard liquor dropped, as people returned to wine and beer.

In current times, drinking rates among young people are dropping now that they have access to legal marijuana, which is a good thing from a public-health perspective.