[runamok]

My pet theory (with some anecdotal evidence) is that a lot of external investors are buying up most of the inventory. And a lot of young people making > 100k will spend large amounts of their income to live in the bay area even if they have to have roommates, etc. Cities like SF and NYC do have the advantage that you don't strictly NEED a car at least in some areas (and of course the gas, maintenance and insurance that goes with it) so that frees up a decent chunk of cash too.

What generally happens is once people start getting married and having kids they move to other states. I have seen this with several friends.