None of the countries that are doing far better than us have anywhere near the level of incarceration that we suffer.
Here (USA) billionaires microdose acid and take molly in the desert. The culture around drugs is entirely different.
While Singapore has a lot of things going for it I wouldn't really consider it more free than Norway, even if drug consumption is substantially restricted there.
You could do the comparison using other crimes instead, but bodies are a more concrete metric. By the way, it's not just Singapore.