You're right that the drug war is a farce, but your reasoning is wrong. Altering consciousness is never going away, even with steep penalties. All that accomplishes is making the externalities of drug law enforcement even more severe.
Consider, for example, that both Trayvon and Michael Brown were high on marijuana when they made decisions that lead to their deaths and ensuing hugely expensive social disturbances. If you care to step out of your upper middle class bubble, it is not at all crazy to suggest that cannabis does in fact have huge negative externalities.
0 - http://en.wikipedia.org/wiki/Shooting_of_Trayvon_Martin#Coun...