I suspect the results may be slanted by two layers of self selection. The majority those that get into trouble tend to be those who have self-selected to be in danger. Second, the stories always report what the survivors attitudes were.

It would be interesting to find out if those who didn't put themselves in danger experience it differently. Even more interesting to find out what hose who died think of the situation. Not sure how you do that but a seance and/or Ouija board might be worth a shot.

Of course the survivors are going to cite their superior willpower. It both makes them seem special and offers an easy explanation for why others died when they didn't. It is the nature of man to flatter ourselves and seek easy and reassuring explanations for essentially random, or biologically/genetically dependent, events.

Biological/genetic in the sense that people with stores of energy, extra body fat, tend to have an edge fighting off hypothermia and surviving starvation. Likewise people with larger quantities of brown fat, fat that helps generate heat, tend to do better in cold temperatures. Likewise people who naturally tend to get frostbit seem to survive colder temperatures longer. They lose fingers and toes because the body cuts off blood flow and heat loss, but are better able to preserve their core temperature. Higher metabolism may provide protection for short term extreme cold as when a person falls into cold water. None of these has anything to do with willpower. They have to do with genetics, body composition and metabolic efficiency.