alt Hacker NewsThis is what I've observed as well. By my own metrics and grades, I was a somewhat bright math minor (near-perfect score in abstract algebra, etc), would have been middle of the pack as a PhD student, may have been below par if I managed to complete the PhD, and almost certainly would have been deadweight as a pure mathematician myself. That's just how the scaling and competitive dynamics have worked out; it's not really something to feel personally bad about, any more than you might feel personally bad about not having the potential to be a competitive figure skater.
EDIT: Uh, actually, it looks like I may have underestimated myself at basically every point here and would have become a basically okay mathematician based on updated priors.
The silly thing about this is that context is everything. I bet it's extremely easy to be a top-tier figure-skater in, say, a small tropical island nation? In a similar way, I very much doubt that you'd really need to be in the top 0.2% of the population to complete a phd. Do you need to be in the top 0.2% of people to compete as a contributor with absolutely everyone else in the whole world at the same time? Well yeah, but at that point the statement is so obviously true that it doesn't mean much.