Banning addictive things isn't as straightforward as people love to believe. Even during the worst theocratic times, you could get alcohol in Saudi Arabia by asking the right people; and Saudi Arabia had way harsher means at its disposal than democratic countries do.
(For the complete picture, my grandpa drank himself to death at 57 and even though he used to have a good income, on the order of 3x as much as an average Czechoslovak worker of that time, he left almost nothing behind. All "liquefied". Other people were able to build family houses for their kids with less money.)