Note that I'm not in favor of either weed or alcohol being as readily accessible as they are now, but there are a few things making that claim a bit dubious. The first is that obviously people are less reluctant to self-report using weed if it's legal. Secondly, the causation could be reversed, i.e. there are other factors in society contributing to both higher usage and larger general support for legalization.

In any case, my point was that simply making something illegal with the threat of "decades in prison" isn't a very good solution. Gambling, drugs, social media, etc. are all "big business", there's money to be made because there's a demand for it. How to solve that I don't know, but just prohibiting it doesn't seem like a good fix.