price dropped and some owners don't have to sell.

because the demand for Bay area good school house is always very high, and most people who can previously buy into those neighborhood usually do not rely on avery salary income. When price dropped to a certain degree, it is perceived that it will be temporary and rebound will occur within a couple of years. People who can endure the cash flow is capable of not selling them. Rental in those area is typically >3000/ month. So it will cover some loss