It is an easy filter for job applicants, who are also likely in debt and desperate for stable work. If they had or could get a decent job in their field of study they wouldn't be applying for factory work unless they were an automation specialist.

> Can you explain how an employer gains any advantage by pointlessly requiring degrees today, when they did not previously? What would that do other than raise their labor costs?

Suppose that people with a degree are significantly less likely to quit shortly after you've spent a lot of money training them on your equipment, regardless of whether what they studied in college has any application to the job. If you have to pay the person with a degree a lot more money then maybe it isn't worth it just for that, but if everybody gets degrees and there is an oversupply such that there are more people with degrees than jobs that actually require them, now maybe you can get someone with a degree for a low enough price to be worth requiring it.

> Anyway, the article is clear that increasingly automated factory work requires more educated and independent employees.

That's just the signaling value again. They're not looking for someone with knowledge of GAAP or materials science or economics, they're looking for someone with the proven capacity to earn a degree by studying those things, because it implies they can also learn to run the machines well.

If not as many people had degrees then it wouldn't be worth paying the premium for one of the people who do, and then people who are going to be machine operators don't have to burn four years of their lives and incur significant student debt just to engage in signaling behavior. Instead the employers would have to bear the (lower, but unsubsidized) cost of more attrition as a result of not having the degree to use as an early filter against low quality employees.