Power+Attitude=Performance
Remember the old adage:
Power+Attitude=Performance?
In this case, clearly there were distractions (I imagine having a jumpseater was one of them)- maybe the emergency checklist for the RadAlt failure (I don't fly Boeings so I don't know what would be carried out) was being read- or the failure consequences was being demonstrated to one or both the trainee pilots- and basically at this critical time the aircraft was not being flown by anyone.
From my recollections of the 737, the trim wheels move at a rather frightening speed and make a noise like nothing else I have heard. Surely, if the power setting had been overlooked, the nose would be raising to maintain the glideslope and the trim wheels would be winding back trying to keep the thing in trim. The consequence was the speed reduced to Vref-40 and the rest is history. I suspect with the amount of drag being produced at that low speed (plus a high nose attitude) the aircraft was doomed just as the Titanic was the moment the iceberg was struck.
Very sad, but why nobody noticed all the clues will have to be determined by the crash investigators. I am convinced the distraction of the third crew member will be the key to this disaster. Had the PF remembered the equation above or the old favourite Aviate Navigate Communicate, we would not be looking at a hull loss and the tragic loss of life that we can now see one mile from the Polderbaan.