It isn't, but it is a part of the exact same problem, in that wages haven't kept up with the costs of housing.  It is much worse on the lower end of the spectrum, but when it comes to places like the bay area, it appears that even those much higher on the pay scales still struggle to find a place to live.  Based on the article, a person would have to earn roughly $120k a year to afford a 2 bedroom appt in the bay area.