Like most people in San Francisco I do not rely on taxis for anything important. If I am where I can hail a cab I will do so. I will not telephone for a cab.
I will also check very carefully any plane arrival or departure at San Francisco airport.
There is one simple reason. If the failure rate is too high in either case the potential user must find alternatives. In the case of taxis, I have been screwed at least twice because of a late arrival by a taxi and had to find an emergency alternative to get to my meeting or plane on time. Two screw ups were enough to permanently influence my attitude toward taxis.
There is no margin for error in the taxi business. All taxis are smeared by the incompetence of any in the business.
At SFO we have a problem that the regular overcast skies of San Francisco significantly impair the landing of planes. Our runways are too close together to allow parallel landings with overcast and the pernicious environmentalists will not allow the building of a new runway in the Bay.
Consequently, I waste a great deal of time checking airplane schedules for both arrivals and departures at SFO. The airport cannot be trusted.