In 10 years not one 747 pilot has ever agreed that shifting the CofG back as far as it was shifted would cause a zoom climb. They have said that it would cause the wing to stall...
BTW "flight idle" is still a good deal of thrust
Not according to Boeing... and it is not "flight idle" but a complete idle mode. According to Boeing, when signal is lost from the flight deck, the engines immediately return to idle. No thrust to speak of at all.
If the aircraft had traded forward momentum for altitude it would not have crashed into the ocean where it did... it would have crashed miles closer to the initiating event location... it didn't... ergo, no zoom climb. I've done the math... right here on FR.