Dear Thrice Gotcha,
Even as I type this I HOPE my answer proves overly cynical...but I am concerned drugs are very profitable for the rich and powerful, perhaps even at government level - making control extremely difficult.
As to what can be done to stop it, this is one of those great concerns that it comes down to each of us common folk to do what we can...non-profit orgs, advocacy, prison reform, concern in our personal lives...
Because drugs can take over someone's life before you know it, and you just powerless to make wholesome choices...the lost potential is immense for both the person AND society.