Earlier quoted context omitted.
It looks like you're being downvoted, so I'll provide a reason. Alcohol is legal. The gangs that formed around producing, smuggling, and selling alcohol (e.g. Capone) are gone. The hope is that once other drugs are legal, the same thing happens to their producers.
Of note, since I was curious as to the answer myself and just found out, there are still 'gangs' (though less the urban variety we're used to seeing) based around moonshining. That prompted me to ask "why is moonshining illegal", and the best (wrong) answer I could come up with was for production and delivery to dry counties. Turns out, it's just a matter of taxation. Moonshiners are welcome to go legit, but they the…
I agree that the main element is taxation.
Very many cigarettes sold in England are smuggled in from EU because of tax. But now people are counterfeiting so some cigs are both smuggled and fake - the quality of some of the smuggled product is alarmingly poor. (But it's tricky to get any sensible information about this because the only people releasing information are the customs / police who want to make it seem as scary as they can.)