It's not just USA, it's pretty much universal, as much as I've seen it. People like to pretend like it's some sort of noble profession, but I vividly remember having a conversation with recently graduated ex-classmates, where one of them was complaining that she failed to pass at every department she applied to, so she has no other choice than to apply for department of education (I guess? I don't know what is the name of the American equivalent of that thing: bachelor-level program for people who are going to be teachers). At that moment I felt suddenly validated in all my complaints about the system we just passed through.