An odd thing about long distance hiking is that you could line everyone up at the start of the trail and you wouldn’t be able to pick out who was going to make it with any more accuracy than if you guessed.
The young super fit hiker that you thought for sure would make it, drops out and the old fat guy makes it.
Here’s what I think: Everyone comes to the trail with a handicap. It’s how easily you except yours and work around it that makes the difference.