Top-level hiring decisions favor those who've been tested, even if their performance was crap
People associate failing upwards with public-facing jobs (athlete, CEO, movie star). This is less due to their actual job performance—though that obviously is an aspect—than the skittishness of those who hire them around taking any kind of risk on someone untested (even if they'd likely be better than someone who's mediocre but comes with experience).
This explanation, obviously, implicitly favors the white, the male, the straight, the wealthy.