Church Attendance per capita hit an all time high.
Admissions to mental hospitals per capita hit an all time low.
We're getting none of those from our decades-old War On Drugs.
True, but according to the CDC currently 51% of people use alcohol on a regular basis. Only 19% smoke, Only 8.7% use illicit drugs of any kind and only 6.6% smoke pot.
Since pot use is still limited to a small portion of society, you wouldn't see a big improvement.
What we get with the drug war is avoidance of bipolar, schizophrenic, and other psych disorders which do impose a cost on society from disability claims and unpaid medical fees, to dudes driving their tractors over rows of cop cars.
In any event, you're going to have a drug war even if you legalize pot. Because there is always something more dangerous and more addictive out there, that you don't want on the streets. Legalize pot and you're still fighting a war against cocaine, meth, ecstacy, bath salts and mushrooms.