Using the standard practice of pitch + power to maintain safe flight does not work if the aircraft is ALREADY stalled, which was the case here
Actually, I think they did have a chance to use pitch/power. The BEA report states that the aircraft was stalled for the last 3m30s of the flight. The autopilot/throttle kicked out ~4m30 seconds before the recording stopped and that minute between the auto-pilot/throttle leaving and the actual stall appears to be a pilot induced climb with no change in power settings = pilot induced stall.
Of course, once in the stall recovery is a different matter.