I think Sonja's study does more than "prove a point" - it also illustrates exactly _how_ "luxury" housing helps everyone, which is a huge sore point in local po

I think Sonja's study does more than "prove a point" - it also illustrates exactly _how_ "luxury" housing helps everyone, which is a huge sore point in local politics. Understanding of the nature of how flexible preferences and different levels of wealth interact is still a useful exercise. It would be very difficult to devise a study to prove whether exogenous demand is real, but a casual examination of San Francisco suggests that it is not - SF has built very little housing and still consistently out-attracts many other metro areas.