Do cities in Western Europe and Nordic countries also have this issue? I frequently hear they have excellent social support that prevents this. But, I haven't seen data either way.
I don't know the full extent of the issue in San Francisco.
But there is an increase across not just Western Europe but Australia, Canada etc. And not just homelessness and drug use but upstream factors like inequality, poverty, cost of living etc.
So many people have been living on the poverty line that it doesn't take much to push people over.
Advanced Asian cities which combine rapid zero tolerance policing with the resulting social conformity don’t have these issues. There has been a rise in drug abuse but it tends to stay out of the public view, again due to policing.
I remember visiting nyc and seeing people shooting up in the street while the police were watching. Obviously the problem is lack of enforcement- and if petty crimes aren’t enforced even with just small punishments, then more serious crimes accelerate.
I think he's pointing out that people who commit serious crimes usually have a prior history of smaller, petty crimes that they were not given meaningful punishment for.
The data certainly supports this observation, and I can dig out supporting evidence if it's in doubt (at least in NYC, Dublin, and London. I'm not familiar with SF).