Plus the court's definition of liability has been expanded in civil suits to include anyone and everyone who had any contact whatsoever with the drinker. Plus the penalties have increased.
Legal status aside, there are many other reasons (price, taxes, social stigma, etc.). Don't let Know your rights (aka MrLeRoy) define and limit the scope of the argument -- a favorite tactic of his.
?
Insofar as nonlegal factors affect recreational substance use, your claim that a drop in drug use must be due to the legal war on drugs falls flat. Thanks for exposing the weakness of your own argument.