> You're saying that as supply catches up to the soaring demand, profits will go up instead of down?
I don't think you're wrong on the larger point that landlords are more likely to be on the side of NIMBYism / NIMBYs are going to be land owners.
But, to an extent this is possible; the price would drop for the additional supply, but the total of (now_higher_supply * now_lower_price) can still be greater than (original_lower_supply * original_higher_price). Depends on how the market demand responds to the additional supply, and how much additional supply there is. (It can happen the other way, too, where the drop in price outweighs the new profit from the new supply, and total profit drops.)
… so it kinda requires an idea of how the additional supply would cause the price to change, beyond what I suspect most landlords have. And a foresight/long-termism that I also don't think exists. And if you're a small time landlord not planning on building additional properties, then your supply is always 1, and if the price does down, obviously then too the product does. And I think in SF, the additional supply that is needed, from a more moral standpoint of "people need to live, commuting is bad for the environment and people's health", is crap tons of additional housing. The price to rent could halve and still be too high.