IF it was pilot error and the crew allowed the plane to get too slow, THEN better stall warning must be included into the plane's equipment. Instead of a shaker and a pusher...better put in a HORN, then shaker then pusher.
Every place I've flown, the full attention of the crew is to be focused on the level off during the last 1000'.
Because the NTSB is still unsure about the airspeed, I suspect that something unusual happened to it.