People will live in the best place they can afford. This means prices will always be driven by the income level of people in the area.
If you suddenly built more housing in SF. You’ll actually just get more people who can afford to live in SF moving there. That’ll drive the prices right back to where they were.
Demand would have to drop, while you expand supply. Remove tech jobs from SF and demand will drop, lowering prices. If enough external people don’t wish to move there and you’re building, then prices drop.
Effectively, demand always massively outstrips supply for living accommodations
As a thought exercise: imagine it was $100/month to live in a 3Bed, 2Br house in Houston. You’d have 100m people want to move there.
Keep moving that number up, at some point you’ll get supply and demand meeting. If you add 1000 new houses, it’ll barely impact demand because you’ll have 1000 people willing to move for a $50/month reduction in cost. Then prices will be right back where they started.
Unless you can build 10k units or 100k units prices won’t meaningfully change from supply side factors alone.