Thinking out loud, the thing is that there are analogs to the non-feed upkeep costs (shelter and farmer/veterinarian labor) for humans. Though some work, like composing poems, requires little more than physical sustenance to be performed well, most human production requires complementary inputs, principally various equipment or machinery. The question then comes down to whether you want to invest in such human-augmenting equipment as opposed to a fully automated solution.
For example, suppose total production is AhLαK1−αh+ArKr. Then optimal capital allocation means Kh/L∝(Ah/Ar)1/α so that human-augmenting capital falls as robot productivity increases relative to human-in-the-loop productivity. Then the real wage, the marginal product of labor, is proportional to Ah(Ah/Ar)1−αα. If both Ah and Ar grow exponentially, the condition for the wage to remain constant is that Ah grow at a rate 1−α times the rate at which Ar grows (where 1−α is traditionally taken to be 1/3). (Google Sheet simulation)
In this toy model, it is conceptually possible that human-augmenting technology, Ah, advances sufficiently quickly relative to full automation, Ar, to keep humans fully employed (at above subsistence wages) indefinitely. (And sufficiently deliberate policy could help.) But if, instead, Ah continues growing at 1-2% annually while Ar takes off at 10%+ rates of growth, human labor eventually becomes obsolete (in this toy model).
This seems like a whole other essay, rather than an edit to this one, though. I’m guessing the analogy to Ah for horses was relatively fixed during 1910-1960.
Thinking out loud, the thing is that there are analogs to the non-feed upkeep costs (shelter and farmer/veterinarian labor) for humans. Though some work, like composing poems, requires little more than physical sustenance to be performed well, most human production requires complementary inputs, principally various equipment or machinery. The question then comes down to whether you want to invest in such human-augmenting equipment as opposed to a fully automated solution.
For example, suppose total production is AhLαK1−αh+ArKr. Then optimal capital allocation means Kh/L∝(Ah/Ar)1/α so that human-augmenting capital falls as robot productivity increases relative to human-in-the-loop productivity. Then the real wage, the marginal product of labor, is proportional to Ah(Ah/Ar)1−αα. If both Ah and Ar grow exponentially, the condition for the wage to remain constant is that Ah grow at a rate 1−α times the rate at which Ar grows (where 1−α is traditionally taken to be 1/3). (Google Sheet simulation)
In this toy model, it is conceptually possible that human-augmenting technology, Ah, advances sufficiently quickly relative to full automation, Ar, to keep humans fully employed (at above subsistence wages) indefinitely. (And sufficiently deliberate policy could help.) But if, instead, Ah continues growing at 1-2% annually while Ar takes off at 10%+ rates of growth, human labor eventually becomes obsolete (in this toy model).
This seems like a whole other essay, rather than an edit to this one, though. I’m guessing the analogy to Ah for horses was relatively fixed during 1910-1960.