Luckily, the branch library where I hang out is too far from city center for it to get many of the homeless population, but our downtown main library certainly does. I was working at a psych hospital back in the early 80s when the word come out through the psychiatric profession that people who had been in custodial care were to be "mainstreamed", supposedly for their benefit, but really because outpatient care costs less than inpatient. I suppose that it was fine for some, but many went directly from their wards to shelters and living under bridges, and a large proportion of them never seek any outpatient care at all.