Could it be some countries have unique demographics, climate, or cultural factors not found elsewhere?

I'm not saying SF is blameless, but what works in Japan or Norway isn't guaranteed to work in SF.

It could be, but the broader frustration is that these factors you cite aren't even researched on a local level.

You say the trains run on time in Japan, and people don't respond by researching transit infrastructure in Japan to figure out why that is. They respond by throwing their hands in the air and staying it's impossible, unfundable, politically untenable, whatever fluff reason that's indicative of an unwillingness to think analytically about the problem.

The underlying cause is that there is no thought or scholarship in local government, just electoral risk assessment.

Without arguing about what factors cause it, it's undeniable that

1. Non US rich countries have much less mass shootings.

2. Non SF major US cities have much less street poop.

This shows that neither problem is unavoidable.

I don't think you got my point. I recognize that neither problem is unavoidable. We agree that both can be solved, and even that we should look to others who don't have such problems to find solutions. However, calling "simple" the process of getting one country to broadly "be" like another country is just absurd and unhelpful. One could go around throwing that out as a solution to literally any unique problem had by any country. It's the nation-scale equivalent of telling a depressed child to just be happy like the other kids.

I actually agree. I didn't and wouldn't use the word "simple". My point was more that it's "possible".