Silicon Valley’s ugly rich-poor gap: What’s the tech world gonna do about it?

It's important to remember that this sort of gape has enormous costs, costs that could be avoided if they were addressed from the get go. When there are good jobs and affordable housing, crime rates are lower (see http://rri.wvu.edu/wp-content/uploads/2012/12/REU2001-19.pdf ), and there is less need for spending on security, police, etc. The average prison inmate costs $47,102 a year, while adding little to nothing to the economy (some prisoners work for less then a dollar an hour, so they do have some minimal economic output).

That's paid for in taxes. That's a good middle class wage, and could support a family in the city, or if spent by the government, could go towards useful services like public transit, or education. Instead it supports one individual, and doesn't include the value of their lost labor, the cost of the trail, and other associated costs.

In fact, given that education reduces crime rate (see http://emlab.berkeley.edu/~moretti/lm46.pdf ), and also prepares individuals to work, and given that investing that money in education, for example, provide a 7 to 10 percent annual return for the public in terms of increased productivity, and decreased crime (see http://www.aft.org/pdfs/americaneducator/spring2011/Heckman.... ) income inequality ends up costing tax payers quite a bit more then you actually think.