This is a bigger issue than most people appreciate, and a huge problem for the USA.
There is a specialised trade known as tool and die maker, or just die maker (https://en.m.wikipedia.org/wiki/Tool_and_die_maker) that is fundamental to a country’s ability to create industrial capacity. So far, no automation tool has been able to replace their expertise.
Without die makers, you can’t build tools that make things, you can’t build factories, and mass production in general is dependent on their skillset.
Right now, the USA only has 50k die makers, and the average age of a die maker, including apprentices, is 54. The average age of a master die maker is 73, and the average age of a journeyman is 62. A master die maker can teach about 5 apprentices to the journey man level in a work environment, after 2+ years of basic engineering school, in about 5-7 years. A journeyman may generally considered a master after 10-20 years of experience, depending on the nature of their experience.
We don’t have enough die makers to rebuild the industrial capacity of the USA, and we can’t teach the amount we need in less than 5-7decades without some kind of major change in the process of doing so. And since more than half of the master die makers are months from retirement or death, we are in an extremely precarious position as a viable industrial power.
This is why it is extremely difficult to build anything physical in the USA using only USA sourced parts and materials. It’s almost impossible to even get a decent variety of screws and fasteners made here in the USA, and we can’t easy build the machines to make screws because of the critical shortage of master die makers.
If we are to maintain the ability to build and maintain our machines, weapons, and critical infrastructure without being completely dependent on imported tools, supplies, and knowledge, we will have to reinvent the industrial process using automation or something similar to compensate for our foolish exportation and devaluation of strategic skills and capabilities.