You're conflating the internal (lack of) logic from the perspective of the person employed in a bullshit job with the external logic for the existence of this position. Businesses hire people for multitude economically sound reasons and very often from the perspective of the person the job is utterly meaningless except for providing them with a paycheck. That leads to psychic pain. The economic logic is there and moving the needle but the social, cultural, psychological logic is lacking. That is the problem. I think the theory is sound: that disconnect between economic logic and other levels of meaning is at the source of the problem. There's no grounds to dismiss it by reducing all logic to economic logic.