All things being equal, SF has some of the most desirable weather on the planet, so it will always have an high cost of living due to excess demand.
it's a great place to live and there will always be high demand.
there would be more supply if not for restrictive zoning laws. and more supply = lower prices
How do you square this bizarre and obviously false hypothesis with all the times that San Francisco did not have high cost of living, had declining population, etc?
There are plenty of other places with equally great weather and no needles on the streets.