Crime in 2018 (Or Why Are There so Many Homeless People?)

I start off by telling of an amazing crime involving pizza delivery. From there I wonder about the incidence of crime in general, and whether there's any relationship to homelessness. 

My own impression is that homelessness is increasing, this doesn't appear to correlate to an increase in crime, nor does it correlate to an improving economy. Why is that? Why has homelessness not declined significantly during this most recent economic expansion?