Yep, which is why I used the term "more lenient policies," not necessarily non-prohibition. Opium dens were getting more and more problematic in San Francisco[1] until they were criminalized in the late 19th century.
> I mean, people haven't really stopped doing Cocaine or Meth
I don't think the end goal of prohibition is zero use of said substance, but rather its control as to prevent large-scale societal disruption.
[1] https://www.foundsf.org/index.php?title=Chinatown%27s_Opium_...
The point is that prohibition the issue. Being more lenient while still keeping prohibition isn't a half way point, but still keeps the most harmful elements intact.
> I don't think the end goal of prohibition is zero use of said substance, but rather its control as to prevent large-scale societal disruption.
Do you think that prohibition is effectively preventing large scale societal disruption?
Opium was prohibited even after the opium wars. That's not a good example of non-prohibition but instead the knockon effects of worst of both worlds informal, capricious quasi-legality.
> The counter-example is Prohibition (which was an abject failure), but maybe this is (at least in part) due to the cultural importance of alcohol of so many people. I don't really think cocaine or meth are such cultural lynchpins.
I mean, people haven't really stopped doing Cocaine or Meth, and the most negative effects of prohibition (extremely violent organized crime) still seem to be present.