It's the asset forfeitures and federal grant money for SWAT teams that drive the major crazyness. Follow the money.
A hundred years ago, there were no laws against cocaine or heroin. Prior to passage of the Harrison Narcotics Act in 1914, people could buy opiates in the local pharmacy. While there were a number of addicts, social controls kept a lid on things.
Since there was no welfare, anybody who became an addict ceased to be productive and became a burden on his or her family, who would have a strong incentive to deal with the addict. Not surprisingly, drug abuse became a big problem around the same time that welfare programs eliminated much of the consequences of allowing somebody to become an addict.
Bingo. EXCELLENT point. Thanks for making it. I think I'll use it.