As someone who lives in one of those cities, it seemed like a clear correlation could have been made. It was chance to unite a rural and an urban problem across race and I thought it was a missed opportunity. I still enjoyed the book, but think it is even more powerful when read in tandem with a book like Evicted  that views the problem from another perspective.
Anyone interested in reading more on this topic, I rec. this book. It's about people who are near-homeless, not fully homeless, but it's one of the best things I've read on the topic. The author lived with the subjects for several years & does a superlative job of telling their story in that sort of explanatory way (not judgmental or absolving) that HN readers seem to appreciate.
(excerpt of the book here: http://www.newyorker.com/magazine/2016/02/08/forced-out)
In theory that's true, but in practice many U.S. municipalities have restricted the development of any new housing to the point that Section 8 vouchers are impractical due to costs and simple apartment availability (http://www.vox.com/cards/affordable-housing-explained/supply...). Without doing something about NIMBYs and local zoning processes, Section 8 vouchers will not be effective.
Matthew Desmond's book Evicted is pretty good on this point (http://www.amazon.com/Evicted-Poverty-Profit-American-City/d...). I've written or worked on Section 8 proposals, as well HUD 811, 202, HOPE VI, and related programs (see http://seliger.com/2008/07/27/reformers-come-and-go-but-hud-... if you're curious); the people who run them, especially in high-cost cities like LA, SF, NYC, and Seattle are well aware of the problems that local zoning imposes on affordable housing.
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