There's been quite a bit of new housing added in the past decade or two, hasn't there? A bunch of SoMa has undergone semi-recent conversions from industrial to residential use, and there've been several large condo buildings going up (Millennium Tower, Infinity, One Rincon Hill, Paramount), as well as hotel/condo combinations (Four Seasons, St. Regis Museum Tower).
Not really, when you think about the number of units in those buildings total (I'd guess a few thousand at most) versus the boom in Bay hiring.
I lived in NY before SF and at least subjectively, it feels like more new (incremental, not replacement) apartment units were put into say, Sixth Avenue between 23rd and 35th in the last decade than in all of San Francisco. (I'm guessing that is about ~3,000 units based on 10 blocks of ~40-story apartment buildings on two sides of the street.) SOMA lofts are nice but at only 3-4 stories high, they don't add a lot of units to the count.
SF is the second most densely populated city in the US behind NYC. If we need more housing, we need to build upwards.
See the article I linked to above: "Meanwhile, San Francisco—one of the most expensive cities in the United States—added just 418 new housing units in 2011, the fewest since 1993. What’s more, 149 existing units were removed, leading to a nearly nonexistent increase in housing supply."
That's a 1-year measure, which has a lot of fluctuations; something like a 10-year measure, showing a general trend, is more interesting to me.
Clicking through a few times to http://blog.sfgate.com/cityinsider/2012/05/17/after-a-lull-s..., 2011 is apparently an anomaly, and around 20-25k new units (net) were added over the past decade. In addition, 2k new units were approved in 2011. Still not too high, admittedly (a 7% increase in housing stock over a decade).
During that same decade, the population of SF grew by about 60,000. 25K net new units in a city with 60K net new residents (and one of the lowest percentages of children in the country) is effectively no growth in housing stock.
Additionally, a lot of those 25K units are not market-rate housing (they're for low-income) which means that for market-rate housing, the numbers would look even worse since most of the new residents are not eligible for low-income housing.
