I read a crime story today. It was about a modern day expedition climbing Mt. Everest, a client determined to reach the top, and someone else in the party looking for revenge against that person. It's a good story in itself―the author's name is William Hall―but it also started me thinking about those who climb big mountains like that.
Some Sherpas do climb Everest without bottled oxygen. Ang Rita Sherpa did so ten times. No sane Western climber would attempt that. It's also true that the the Sherpa culture's religion holds that the Himalayas are sacred.
There's probably a connection between these two things. Sherpas revere the mountains as loci of godly activity. This encourages a certain carefulness.