The probable answer to that question "why did nobody, ( 3 of them) recognize the stall " is described in the the 1984 Charles Perrow book , " Normal accidents " describing among other things the 3 Miles Island nuclear accident.
There is a difference in Human factors between what is logical on paper, and how humans faced with unknowns and stress react. Training is supposed to help bridging that gap. Training for stall recovery in one thing, but recognizing a stall starting with wrong indications on displays is another.