Originally Posted by
AerocatS2A
It wouldn't be a big deal. Those jets on the ground would stay there, and those in the air would land in an orderly fashion. There are places where passenger jets operate in and out of airports that don't have any controllers at all.
Despite what they might like you to think, we don't really need them 
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In non-ATC airports, pilots are aware and operate accordingly. This is quite different from a major international airport where flight crew know that there are many a/c in the same airspace and expect a highly-managed environment.
On the night in question, there was a long queue of flights lined up for landing. If everything went smoothly, flights may indeed have landed in 'an orderly fashion'. But things don't always go smoothly. Assume that the single controller had, say, become unconscious. It one flight had failed to clear the runway in time (perhaps not knowing which exit to take, lacking tower instructions), or a vehicle encroached on the runway, there would be no way for the following flight to know that and execute a go-around. How long would it take for the 'spare' controller to become aware of his/her colleague's absence? How long to run upstairs and assimilate the situation?
The single-controller situation seems to me to be a risk. That might be acceptable in a small, remote airport with few flights. But in SFO? With ground and airport full of a/c and vehicles? A major international airport should not be allowed to take that kind of risk.