Not really true:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4472929/
Totally comparable to the US, Norway being an exception (as usual).
> They blow the US out of the water on every metric.
The US is a very large and diverse country and it's not structurally comparable to Germany, Netherlands and much less Norway (with 22% of GDP being oil exports). That would be cherry-picking. To draw any conclusions on the effectiveness of incarceration would require more careful analysis.
> I can't fathom what gave you a different idea.
Crime statistics and crime aren't the same thing. The point of prison sentences is no just punishment, it's deterrence. If you rarely convict anybody, your prisoner's rate is low, but the criminals are out on the street knowing they have nothing to fear.
https://www.washingtonpost.com/news/worldviews/wp/2016/02/16...
http://www.spiegel.de/international/germany/human-traffickin...
https://www.handelsblatt.com/today/finance/gangsters-paradis...