Fascinating paper that I'll have to dive on later. I don't know that I understand it well enough to consider the "out of their own apartments" claim. What page supports that? I saw the 70+% of cost is labor. I confess I was surprised not to see liability insurance in there.

Edit: Realizing I may be reading the original comment wrong. I don't remember the apartment claim on my first read, so I thought you added it with your edit. I'm guessing it was there and I just didn't remember it?

What percentage of the labor costs are being used to paying the laborers rent? How much is it in paying the laborers food? For healthcare? For education? How expensive are all of these things in San Francisco compared to other cities?

Now how correct are you?