They used to be able to test candidates using aptitude testing. But back in the 60's Griggs vs. Duke Power prohibited such testing on grounds of racial discrimination or disparate impact. So companies had to come up with other ways to screen out unsuitable candidates. They settled on requiring college degrees instead.
I briefly worked for an employment agency in the 70’s.
Amazing what some companies “expected” us to do to send them only”qualified” applicants.
Hint hint wink wink