I don't understand

While riding the train through Los Angeles I get views of neighborhoods not seen from the freeway. The numbers of abandoned buildings are shocking to me--it's hard for me to understand why, in a town with such exorbitantly high real estate prices, there are these large abandoned structures.

It's what I thought about as a I read through this photo essay at Sweet Juniper about an abandoned historic school in Detroit. It opened my eyes to a major challenge facing anyone who aims to rehabilitate urban buildings--I had no idea that scrapping was so rampant and so destructive. And I wonder why urban blight isn't being addressed by any of the political candidates (at least not that I've heard)?