of course workers will be replaced. perhaps a great many of them! "all" however, is an awfully big ratio, and assumes away the most interesting part of this discussion in the name of writing a piece with a compelling title. what I would say is that tasks and production processes do not exist a priori of production; production is itself a dynamic process where the input tasks are constantly being discovered and refined. thus I would expect, in the long run, for humans, firms, and the economy to be dynamic in ways that are hard to predict but ultimately produce jobs that humans can do. some of this will be because of simple or complex human preferences, some of this will be because of your apparent villain 'comparative advantage,' and some of this will be not quite because of either of those things but because of the intrinsic dynamism of people and of the world. now, this does not mean things will go great! the agricultural revolution probably sucked for many, I'm with James Scott on that one. ai could reconfigure the world in a way that is bad for many people, but assuming the conclusion of "all" negates precisely this more interesting and complex debate.