If neither the worker nor any entrepreneur can think of a profitable task that requires that worker’s skills and capabilities, then that worker will go unemployed indefinitely. Over history, this has happened to many other inputs to production that were once valuable, from whale oil to horse labor. They are no longer needed in today’s economy even at zero price. In other words, just as technology can create inequality, it can also create unemployment. And in theory, this can affect a large number of people, even a majority of the population, and even if the overall economic pie is growing.
Link · Chapter 11 Implications of the Bounty and the Spread