I'd like to see someone mass produce stackable prefabricated units out of pieces and assemble them into multi-floor apartment buildings, increasing the number of aparments on offer very fast and driving costs down. Unfortunately, I think the problem here comes down to regulations. It's hard to acquire land. Much of the bay area has laws preventing you from building new housing much higher than a few floors. The property taxes are very high, which also makes it difficult to offer low cost housing.
My general impresion is that the bay area does not want to grow... Or at least, much of the existing homeowners, the NIMBY crowd, don't want it to grow. They want tech people to get out and for things to go back to how they were in the 1980s, while maintaining the price of their own homes as high as possible.