I've lived in the San Francisco Bay Area most of my life, except college and my 4.5 years in the Army. Homelessness has always been a problem here, and has gone in cycles. The mild weather is part of that. Your haves/have-nots comment isn't far off, in my experience, and has been getting worse in the Bay Area, again, because the cost of living is so high and because there are so many high-paying jobs. However, for all the people who appreciate their high paying jobs, they still want to be able to eat out at restaurants, get their cars fixed, have emergency services, have quality public schools, and generally have other services available to them. That's an interesting economic problem, exasperated by the housing limits.
The Bay Area, more than other areas, is geographically constrained, and the suburbs have been staunchly protected/limited in growth by zoning laws. In the last two decades, it has become much more fashionable to live in the big cities, but rent control, prop-13, and other property-rights issues have prevented even San Francisco, Oakland, and San Jose from allowing much growth. The state legislature is on the verge of forcing California's cities (including the suburbs) to build more high density housing. That will help, but not solve, the cost of living issues. And frankly, home owners like me benefit from the cost because of the equity built up (once you get on the escalator). I'm not especially worried about the higher density housing impacting my property value as people will still want to live in single-family homes, where possible, but there are lots of people freaking out about it.
