To add to the discussion, and your mention of boring assembly line work, a valuable quote (that occurs several hundreds of pages after the pin factory observation) from Smith's Wealth of Nations, written in 1776.
> The man whose whole life is spent in performing a few simple operations, of which the effects too are, perhaps, always the same, or very nearly the same, has no occasion to exert his understanding,or to exercise his invention in finding out expedients for removing difficulties which never occur. He naturally loses, therefore, the habit of such exertion, and generally becomes as stupid and ignorant as it is possible for a human creature to become.
> The torpor of his mind renders him, not only incapable of relishing or bearing a part in any rational conversation, but of conceiving any generous, noble, or tender sentiment, and consequently of forming any just judgement concerning many even of the ordinary duties of private life. Of the great extensive interests of his country he is altogether incapable of judging; and unless very particular pains have been taken to render him otherwise, he is equally incapable of defending his country in war.
> The uniformity of his stationary life naturally corrupts the courage of his mind, and makes him regard with abhorrence the irregular, uncertain, and adventurous life of a soldier. It corrupts even the activity of his body, and renders him incapable of exerting his strength with vigour and perseverance, in any other employment than that to which he has been bred. His dexterity at his own particular trade seems, in this manner, to be acquired at the expense of his intellectual, social, and martial virtues. But in every improved and civilized society this is the state into which the labouring poor, that is, the great body of the people, must necessarily fall, unless the government takes some pains to prevent it.
Vehicle production lines are now heavy users of automation, and workers skilled not only in assembly, but in process improvement, scrum, lean. Not simply being manual workers is to Amazon's benefit, as it was to Ford for he recognised the impact an individual worker had on the end-to-end production; embodied in concepts like TPS, lean, six sigma, but with long histories.