To try to understand why homelessness feels so much worse an California than in Europe, I did some very basic research (which I also posted on a similar thread once before). The numbers are shocking:
San Francisco population: 884,363 (2017/Wikipedia)
San Francisco unsheltered population (conservative): 6,600 (7,499 SF self-reported homeless count * 88.2% HUD estimated unsheltered rate)
Unsheltered population rate (conservative): ~0.75% of residents (my calculation) - nearly 1 in 100!
Compare that with London, a city also experiencing a homelessness epidemic due to explosively rising housing costs:
London population: 8,825,000 (2017/Wikipedia)
London unsheltered population: 1,137 (homeless.org.uk)
Unsheltered rate: ~0.01% of residents (my calculation)
Homelessness rates in SF are absurdly high. In fact, there are more unsheltered homeless people in SF than the entire country of England(!):
San Francisco unsheltered population: 6,600 (2017)
England unsheltered population: 4,751 (2017)
They are not equivalent situations obviously, but somehow a country with a population greater than the state of California manages to have fewer homeless people than one relatively tiny city in California. Something is very wrong.
Homelessness is a complex issue with lots of intertwined causes and no single solution. Not only is affordable housing an issue, but mental health treatment is an equally important problem. I don't have the answers. But I do know that it is a public health crisis and we are currently completely failing to solve it. We need big changes if we actually care about addressing it and we as a country definitely have the resources to do it.