Until you have a sit-down with the political players and agenda people.....to agree to categorizing people....none of this will be resolved and you will just throw money into a pit.
How you categorize people? Well....into four groups:
1. Drug addicts.
2. Mentally unstable.
3. People with no drug issue and no mental issue.....having a valued job skill.
4. People with no job skill, no drug issue and no mental problems.
Group #3 are the ones that you'd want to help relocate into a low-cost housing situation, some job coaching, and some life skills jobs. They will require a year of serious attention but can come back.
Group #2 needs a one-way ticket to a facility that has a fence, and don't really need a real urban environment.
Group #1 can be offered a one-time rehab deal. If they fail....don't waste time or money....just shuffle them into a fenced area and hold them in a prison type environment.
Finally, Group #4....this is the group has the highest cost....you need to provide twelve months of real job training, and a boot-camp atmosphere. They also don't require a highly urbanized atmosphere.
Yes, what I'm hinting is that you need to remove around fifty-percent of most of these people from SF, Portland, or NYC. They can be put into a pretty remote place and forgotten about.
If you don't have any willing nature to do this.....just write a simple rule that no more than $1,500 a month can be spent on any homeless guy/gal, and limit the public 'pain' involved.