Give the corresponding housing crisis in the Bay Area, one wonders if the solution is to "simply" start converting office space to living space until the corresponding demand for office space recovers from a combination of increased demand and decreased supply. Now I'm sure there are all kinds of challenges to doing that, engineering, zoning, other practicalities, but it seems overall reasonable to me, though perhaps…
Those commercial spaces make it incredibly easy to build them however you like. The access to plumbing and electrical would make it simple to convert them into small dwellings.
Modern office buildings only have plumbing available in the center of the building. The flooring is designed to function as a highly efficient membrane. If you start punching holes in the flooring to place plumbing and toilets away from the central core you weaken the floor membrane to the point where it loses the required structural integrity. If you try to build raised flooring to provide space for the plumbing the cost of the raised flooring becomes prohibitive.
For most large modern office buildings it is cheaper to take them down and build new than to try to retrofit them for residential use.