@Shaokang Being able to work as a unit is a good skill to have and while not everyone is equally worthy in a specific capacity, people are not one dimensional and one lacking at one thing might be better at another. Even if people differ in the sum of their talents also, those without any talent whatsoever are rare. Thus, society is a multi-dimensional hierarchy which benefits all of its members. From those who have much, much is required also. Jesus, not Ayn Rand
As for the army – it’s a unique environment which fosters brotherhood between men – aka “male bonding” in the cynical language of science.
I get what you’re trying to say though, communism tolerated and even encouraged mediocrity. Capitalism does, too, in a slightly different way.