Homelessness is a problem easily solved with political will. It is just like health care, we need to spend on prevention not recovery. There are lots of costs, including things like health care. [http://www.newyorker.com/magazine/2006/02/13/million-dollar-...] The hardest problem is preventing a mass migration of homeless once someone institutes a reasonable program. Additionally it is an issue that people generally don't care about. It doesn't resonate in polling compared to jobs and health care so no one invests any effort.