SF politics come into play here as well. There’s been talk of expanding the runways so visual approaches wouldn’t be needed for decades now, but Aaron Peskin seems to have made it his personal issue to kill it at every opportunity.
Have there been any serious proposals or discussion in the last two decades? SFO’s current master plan estimates a growth of 50% more passengers and aircraft operations before maxing the current capacity.
Not since the original proposal ~20 years ago, Peskin has made comments since reiterating that he wouldn't let it happen. We may not be at capacity but SFO has a pretty terrible on time percentage, and traffic slows massively when there's bad weather.