This is because the standard protocol is just to leave the dead where they died.
The top portion of the Mt. Everest, roughly above 26,000 feet, is known as the “death zone.” The oxygen level is only a third of what they are at sea level and the barometric pressure. Those two reason causes climbers to feel disoriented, fatigued and can cause extreme distress on organs.
Climbers in that area are racing against the clock because people don’t usually last more than 48 hours in this area.
[source: All That’s Interesting]