For those who have not flown a 777 and have expressed incredulity and lack of understanding of what could have happened at SFO I would like to explain a few things. I have seen it demonstrated in the simulator and it all happens very quickly.
Being high and fast at 1000 feet led to idle thrust. This led to a decelerating speed.
If you take a snapshot at 500 feet the height and airspeed looked about right. From having been high and fast the crew would have a sense that things were back on track. The biggest clue that things were about to go wrong was most likely the word "HOLD " at the top left of the primary flight display that indicates to those in the know that the autothrottle although engaged will not increase the thrust. Had the word at the top left been SPD (Speed) the accident would not have happened.
From 500 feet the plane starts to go slightly low on the visual profile. As all the private aircraft pilots on this thread have told us if you are low on a light aircraft you add power. That is not the case in a commercial airliner. If you are low you raise the nose and the autothrottle adjusts thrust to control the speed unless it is in hold mode.
If you have gear down flap 30 and idle power and are decelerating below Vref and you raise the nose then the rate of speed decay happens extremely quickly. At this stage if you are not aligned with the runway you inevitably spend more time looking forward and turns involve both ailerons and spoilers and invoke more drag. Apart from practice in the simulator this was probably the first approach either Captain had done where the autothrottle did not maintain the Vref speed. The landing checklist was not completed until 500 feet. The landing checklist in the 777 is electronic and normal airline practice is that when the checklist is complete the non-handling pilot announces it and the handling pilot would then have to look inside the flight deck below 500 feet at a critical time to confirm the checklist was complete. It's a bit like checking your text messages in a car while overtaking. Had this checklist been completed earlier it would have been one less distraction.
So to recap, although at 500 feet height and speed were ok the thrust levers were at idle, the alignment was not right and the nose was then raised with the speed decaying rapidly. It was probably only about 20 seconds after things looked OK at 500 feet that the the aircraft was below 200 feet and the situation was non recoverable due descent rate and lack of speed and low thrust setting. Jet lag does inevitably slow down the recognition process.
I am not in any way excusing what happened, I am just pointing out that it can happen extremely quickly with distractions which is why most 777 operators employ standard operating procedures that involve being stabilised at the right position and speed at 1000 feet with thrust levers back up and speed at vref controlled by the autothrottle and landing checklist complete. None of these happened in the above case which led to a lot of distraction and regrettably in that very busy period it looked like the crew became overloaded and missed the rapidly decreasing airspeed.
As regards changing procedures at SFO. I do not think it is necessary. Thousands of approaches were flown before this without accidents and thousands of approaches will be flown after this without accident. I'd also like to venture that in the unlikely event that the same crew were allowed to fly an airliner again they would never make the same mistake again. An accident is a painful learning experience.