The "countdown to zero" on aircraft using FMS and others is given by a radalt, which works on the actual surface beneath the aircraft. This is obviously much better than a possible false reference of a barometric pressure which is incorrect as soon as the aircraft moves away from the airfield.
I was used to QFE for many years in the RAF. There was an experimental change to QNH in the 1980s but it was only temporary. I think some bigwig frightened himself in an AEF Chipmunk and decreed a return to QFE.