Dan, thanks for your thoughtful and compassionate suggestions. I agree with you that we can do better, and also, that the problem is in part mental illness and substance abuse. I think doing better means first dealing way better with those who really do need help. We are a wealthy nation and we have the resources for that. 

And then, after having helped those who need it, we might be able to revise the options we offer to those who are homeless by choice, who don't have to be. I'd like to see us offer respectable public sector work for decent pay (cleaning up parks, etc.) to help them get back on their feet. 

And, for those who choose not to work, offer them decent clean campgrounds, with facilities; and at the same time insist that choosing homeless is not a license to camp in public parks or streets when decent sites are available.  

We can be compassionate for those in need and still regulate sleeping in parks and public squares.