I guess I'm realizing I never approached this from a standpoint of expecting top people to stay on top forever, so the inquiry seems a little misguided to me. E

I guess I'm realizing I never approached this from a standpoint of expecting top people to stay on top forever, so the inquiry seems a little misguided to me. Even if you manage to dominate your field, in the very best case you're going to grow old & die someday. That's the pessimistic, decay theory. Or there's the optimistic, "progress" theory: If you believe humanity is on a more-or-less continuous arc of steady progress, that means somebody better is always coming along sooner or later to surpass your work.