We are almost there. Just a few last steps need to be taken and recreational drug use will be totally eradicated from the planet. Like smallpox.
At the most, I see another 26 years and another trillion dollars... maybe.... that would be a worst case scenario. I can't imagine it taking any longer or costing any more.
After that, we can eliminate alcohol. The previous prohibition has given us experience to learn from. Combine that with the drug network we have successfully set up and will no longer be needing, and alcohol should be eliminated in a year or two after the drugs are gone. I'll bet we could even start now, and see immediate positive results.
Just think, in a few more years, no more drugs, no more alcohol, the only thing we'll have to worry about is sex. But with the drug network and a few dedicated years, perhaps we could eradicate sex too? And then life will be perfect. I just hope I live long enough to see it.