I always wonder about that. I've never worked at Amazon, but I've worked at places with people who really, really, ought not to be working in computer software - yet they blunder around, causing problems for everybody else, because nobody knows how to or can think of a way to get rid of them.

OTOH, I think I'd be insanely stressed about being judged unfairly for things outside my control (or even being made into a sacrificial lamb) in an environment like that. Even if they kept telling me everything was fine, I'd feel like I had the sword of Damocles hanging over my head all the time.