Together with his climbing partner Andrew Irvine, Mallory died on the mountain in 1924. People still speculate about whether or not they might have reached the summit first.
(Right: climber Graham Hoyland, in the sort of garb Mallory and Irvine wore. BBC News.)
Mallory's body was found in 1999. The camera that the two had carried, which might have answered the question, still has not been found. (You can develop old film—I processed some once that was fifty years old and got usable images, and I did it without special know-how.)
The BBC reports that meteorological researchers suggest that unusually low atmospheric pressure might have contributed to even lower oxygen levels than usual, further hampering them. (Hat tip: Cronaca.)
That link led me to another BBC story from 2006 about climbers tackling the mountain dressed in replica 1920s climbing clothing—and liking it, Norfolk jackets and all.
(You may insert your comment about steampunk mountaineering here. It's the goggles.)
Following the discovery of Mallory's body on the north face of Everest in 1999, a team of forensic textile experts from Lancaster, Leeds, Southampton and Derby universities embarked on an experiment to recreate the outfit from samples of Mallory's clothing which had been preserved in ice.
The three-year project, lead by Professor Mary Rose and Mike Parsons, revealed that Mallory's clothing was highly effective at providing protection at high altitude.
The layered natural materials used to construct the garments were found to be excellent at trapping air next to the skin.
The outer layer of gabardine was hardwearing and water-resistant yet breathable. But the clothing was also lighter than modern gear - the lightest ever to be used on Everest.
Parsons said: "The results stand out as a challenge for future outdoor innovators because Mallory's clothing and footwear was 20% and 40% lighter respectively."
I also flashed back to a talk given by a member of the local Search and Rescue group, who expressed horror that people go into the mountains in non-synthetic-fiber clothing.
So who is making the gabardine jacket?