Great question, and there are multiple explanations that can work, although I disagree with the previous poster:

There is more than one hierarchy of competence. For each occupation, hobby and skill there's it's own hierarchy. So if there's ~30 hierarchies, approximately half of competitors are going to be in top 2% of at least one.

Edit: and if we're talking about purely monetary measures, have a read: https://www.wsj.com/articles/SB10001424052748704409004576146...