Earlier quoted context omitted.
It also constrains supply of real estate, driving up the value for property owners.
12 floors is huge. Nearly every building in Paris is 6 floors and it is already at near the maximum density humanly acceptable in my opinion. There will never be enough supply in some place, especially with speculation and foreign investors. The situation in NYC and these cities is nothing like SF.
Regarding Paris, at the current density, maybe it would be better to have higher building but with a smaller ground footprint (not sure if it's the right term), to leave space free for more parks?