I'm sure people thought like that when agriculture got automated and didn't need as many people any more. Higher productivity shifts people from industry to industry. There's often a lag between the death of one industry and the rise of another.
Just because it was true in the 19th and 20th century that human resources can reallocate from agriculture to manufacturing does not mean it will continue to be true in a future context.
Every day our R&D is chipping away at the necessity for a human labor force until we get to the day we have 0 percent employment.
