Unpredictable weather, falling rocks, slippery walls and extremely steep climbs only make the trip more dangerous. Some difficult mountains are not tested very often which is why they don’t claim a lot of victims. Others, like Everest, are more popular, which means more people trying to reach the top, resulting in more deaths.
Classifying the most difficult and dangerous mountain climbs is not easy. Numbers can be taken out of context, anecdotes can be exaggerated and assumptions can be wrong. Also, climbing can be less difficult than descending because people are exhausted and cold, but still have to make it down alive.