I could believe that, but the question that most people are asking is not "What is the average rent that people who choose to stay in the Bay Area are paying?", it's "If I choose to move, can I get cheaper rent?" Certainly I saw that at the higher end of the market in 2009. (The low end of the market - where most people are, and hence the biggest contributor to the average - moved much less then, because there was much less room for it to move.)

I wonder if house prices will also behave similarly. Right now, the "mainstream" market (i.e. the house that working professionals can afford on income and mortgage without being independently wealthy) tops out at about $2.8M-$3M in Mountain View or Los Altos, but there are a lot of houses selling in the $4-6M range that presumably are being bought with stock options. Could perhaps see a collapse of the top end of the market down to the mainstream real estate market if the stock market collapses.

Averages of all rentals are going to be less indicative of reality due to the fact that low income, mid-income, and high income luxury rentals don't necessarily move in lockstep.