Okay then even simpler, management likes having workers they can physically see and thinks it makes them more productive. Amazon may relentlessly pursue efficiency, but they also make choices in how they do that based on their own culture. For example, if they paid their employees more but weeded out all but the best employees, which is the strategy Netflix uses, that might also increase efficiency more than just cycling through employees like disposable robots. But they don't do that (or even try it) because that isn't their culture.