Read the news articles on the subject. There's a vast number of gainfully-employed people whom don't wish to fritter their relatively meager earnings away on techie-inflated rent. Most people in the area cannot legitimately afford to live there as they would be spending more than a sensible amount on housing because they can't ever hope to earn enough to be considered middle-class. Still, the area needs janitors, cooks, teachers, bus drivers, human resources and more non-techies whom rarely make much in a normal American city. Instead, they make some sacrifices to keep more of what they earn and opt-out of following the other lemming off the cliff into perpetual debt peonage.