[chongli]

It's only a tragic reflection on the city if you assume all the homeless are born and raised there. How many of those migrated there from colder climates? How many were given a bus ticket by their home city and sent there?

SF spends an absolute fortune on homeless people. That, coupled with its temperate climate, makes it a magnet for many types of homeless people.

[ihaveajob]

Correct, but I have never seen such concentration of homeless people anywhere in Spain, where climate varies significantly as well, and economic conditions are historically harsher. But there's a safety net that prevents most people from falling all the way down.