I won't go into it in depth here, because it's well off-topic, but my general sense is that "university as a requirement" is mostly about significant changes in the employer/employee relationship over the last 40 years or so, and the short answer here is that there's no longer a perceived value in training and developing your own talent, so companies are looking for plug-and-play employees. A college degree is one way they're looking for that.

Notice all the chatter these days about how colleges aren't doing a good enough job of preparing graduates for the working world. College was never about that. It was always about teaching people to think, giving them a broad skill set to draw on, etc. It was always up to the first employer to convert the raw material of a college graduate into a productive employee.