Not enough people leaving, and not the right people. The people who can’t afford it leave, the people who can stay, that keeps prices up. It’s when the people who can afford say “nope” that’s when prices drop.
“It’s when the people who can afford say “nope” that’s when prices drop.”
But you’ve answered your own question. The people who can afford to stay are not leaving, so the average income level is rising. The home across the road from us just sold a year ago to a young couple “moving up.” They have grade school kids, and enough income to purchase a $2.2 million home! Farm workers aren’t going to ever afford that kind of home price, and as agriculture automates, they will be forced to leave.
The other issue respecting SF Bay Area housing is that there isn’t any land left. Housing isn’t affordable because there is no stock, and little prospect of any large-scale building of same. As it is, people are being forced to commute to their jobs from the Central Valley. I had a guy working for me in a San Jose high-tech company as a warehouse supervisor. He was driving 50,000 miles a year just commuting!