Except that lack of high density is one of the City's more appealing attributes. I don't like the simple call for more housing without any acknowledgement of the consequences.
A CAP theorem for bay area housing policy: Charming, Affordable, Popular. Pick two. And, like Partition Tolerance, you can't drop Popular.
That's a great way to think about it. You can drop popular (eventually it gets to expensive that you reach a new equilibrium and people stop coming!), but it's hard to say at what point in the future that actually happens.
Nobody goes there anymore. It's too crowded.
I wouldn't exactly say San Francisco lacks high density. It is true that it is not nearly as dense as New York, but it is pretty densely populated compared to other U.S. cities. I think it is right though when people say that San Francisco can still increase its density via 4-6 story housing ala Paris without destroying its charm, and without becoming Vancouver or NYC.
SOMA could probably go that route but I'm not sure it'd work elsewhere in the City.