Where are some examples of other places where that has worked? How long would you think it would take to get to the low point and what would that low point look

Where are some examples of other places where that has worked? How long would you think it would take to get to the low point and what would that low point look like in sf? And what makes a city that has reached that low point a place where the homeless wouldn't want to live? I guess I'm not even sure what drove the homeless to sf in the first place.. was it mild weather and lax law enforcement?