

Exactly there are no legal places out and about to smoke so people smoke at home then rather than feeling energetic and pugnacious they are mellow and sleepy so they have neither the need nor desire to drive.
As we speak imbeciles are trying to ruin this by developing testing designed to harass minorities on the side of the road and test whether the have smoked within several days instead of several hours. Soon you may face driving while brown charges for having smoked yesterday because testing cannot accurately measure impairment or recency of usage.

Actually prohibition drastically increases price, perceived risk, and social acceptability all of which decrease usage. If you mean that prohibition doesn’t make everyone stop using that would be a duh. Society would greatly benefit from decreased usage alone due to decreased medical productivity and deaths…
The most famous “failed” prohibition on this side of the water in the US initially decreased alcohol usage to 30% of its former usage immediately prior to prohibition. Eventually it rose to ~60% but didn’t recover to anything like prior levels until prohibition was ended.
There is another notable factor though. This allows all current addicts to continue consuming their legal fix which can be sold at the corner store but incentivizes all these multitudes of legal avenues to shut out new customers or be shut themselves. These new customers those born from 2008-2017 will initially be a small market for any black market sales probably poorly served unlike the market created by prohibition. If less of these folks initially get hooked early there is statistical reason to believe far fewer of them ever will. By the time those born in 2018-2027 reach maturity between 2036-2045 many of the older folks will be dead and the generation above them will have a much lower prevalence of smoking.