Although a valid concern, I agree that if the intent of the post is to determine if San Diego and housing in other desirable locations is suddenly going to collapse because of a change in the working status of tech workers, imo, that’s very unlikely to happen, for all of the reasons that have already been mentioned.
There are definitely many issues that could subdue the current frenzy, and/or even cause some type of correction in real estate markets, but, as an investor, if you’re not over leveraged, that’s not a problem. The demand for housing is coming from many sectors of society, not just one, and, imo, that overall demand will continue to far outweigh the supply for many years to come–we shall see.