And why do we recognize graduates of higher education in the 21st century by making them wear clothes from 500 years ago?? I know "why" but somehow it would be more forward-looking if they were even wearing Starfleet uniforms.
I wonder what today's version of the gown would be. Something that would be impractical for both service work (barista) and brain work (prompt engineer).
Maybe ski gloves or a sling or maybe a respirator with sunglasses.
It's from 500 years ago, but it's also from 50 years ago and from 5 years ago; that is, it's continuous and has not really had a specific occasion to change. Although the fur is usually no longer real.
Oxbridge are not called "the dreaming spires" for nothing; there's a timelessness to the place that all the antique surroundings and rituals accentuate. The 20th century has largely got rid of formalwear as an important concept, but (at least while I was there) the gown wasn't just for graduation, it was for formal dinners, which would be held on various occasions or up to several times a week in the larger colleges for the sake of having a nice dinner.
Some people believe that things from the past have value, and that continuing traditions is good in itself, providing a sense of meaning and community.
I think it's so important to keep universities connected to the tradition they arose out of in small ways like a gown.
It's amazing, when you read the history, how much of today's discourse about the value of a university education, the conduct of students, and the antagonism between university faculty and intellectuals who exist outside the walls of the university is a replay of stuff that happened in the 14th century and every century in between.