Homeless congregate in downtowns because it gives the most profitable begging revenue.  Homeless populations are also surprisingly small, something like %0.5 or less of the population of a metro area.  And then on top of that, most homeless people aren&#x27;t crazy people who shit on sidewalks.  It only takes a few hundred crazy homeless to make a downtown core horrible.<p>They exist because there isn&#x27;t mental health funding to house and manage them. It&#x27;s a tragedy of the commons problem.