People are naturally creative and entrepreneurial. Given the chance and the freedom to build and create, there would never be “surplus” workers. There will always be a demand for people, where people are free to think new thoughts and act on them.
The problem comes when an over-regulated society makes it impossible to act on your creative drive... or impossible at least to act on it *here*.
This is why the more important part of Trump’s promise isn’t his threat to impose tariffs, but his promise to clear out the regulatory weeds that make it to where you can’t build here. When its better to build your automated plant in China than California, you have a problem. Its not just about wages... since a robot makes the same wage in China as he does in Los Angeles.
My problem is I cannot think of one example in history in which society was sufficiently unregulated to permit a contemporaneous Creation of spin off jobs To compensate for the losses generated by new technology.