Easy to say, but it'll never happen, especially in the US (at least not in my lifetime, hopefully my daughters). Too many jobs would be unnecessary if the "war on drugs" was over.
Is this actually true? We've invested an enormous amount in the war on drugs.
In a nutshell, prohibition was far more invasive and far more corrupt than today's drug war. Al Capone was a billionaire in today's money, and the drug lords of yore were willing to exert political influence in a way that maybe happens today in Mexico, but certainly does not in the U.S. Al Capone once walked into City Hall and pushed the Mayor of Cicero (which was a former independent city in the Chicago area) down the stairs and nobody touched him. Politicians and police were openly on the take from bootleggers in a way that is totally foreign to our modern sensibilities (unless you have any familiarity with the developing world).
How much money and weapons are used in protecting bootlegged alcohol these days?
Look at state and local cops, federal prison guards and the BOP, state and local prison guards, federal prosecutors, state and local prosecutors, privately owned prisons operated under contract, government employee unions, state and local police departments receiving billions in tax dollars via "drug war" grants and gear from FedGov, companies manufacturing battering rams for those 4am no-knock SWAT drug raids, etc. Let's not forget the U.S. military and border police.
At least at the federal level, over half of prisoners are there for "drug offenses": http://www.bop.gov/news/quick.jsp
What would happen to all those jobs if non-violent "drug offenders" were released from prison? That would be a tragedy, really.