Their policies are demonstrably at fault though, there are large European cities which face this same dynamic and yet they do not have anywhere near the level of problems that we have in this country.

This seems to be, in large part, due to their policies. Housing is not their primary goal, addiction and psychiatric treatment are. You get housing when you comply, it's the carrot that is used to motivate people to engage with the program.

The author recently did a Joe Rogan podcast and did a very good job of explaining this and it's practical effects and differences in detail.