Ah, yes, of course this is how it works in the US.
Mine wasn't like that (and still isn't). Multiple friends of mine are graduating from NYU this month, and their situation isn't like like that either.
Every school I've ever encountered gives an option to purchase (with some being way more affordable than others). E.g., NYU JD (law school) cap and gown is roughly $98 to purchase (not to rent) this year.
Academics, who attend many graduation events, often end up buying their own gown. I believe you are supposed to use the gown of the university you graduated from, so they must be for sale somewhere.
Once you have your own gown you can customize it. I haven't seen any profs with LEDs additions to their gowns, but adding extra pockets to hide a book or snacks is fair game.
Looks like Ede no longer sells my University gown but https://churchillgowns.com/ does. Again rent/buy.
However, I am shocked to hear that there is not even an option to purchase them at OP’s university. Many people like to keep them, especially the cap at least, as a souvenir, or their parents will keep it. Besides, couldn’t they make more money selling them?
Also, as a souvenir, the tassel, which is decorated with a charm showing the year graduated, is also always (obviously) yours to keep.
It’s very common in America for young people to hang that tassel from their car’s center rear-view mirror.
My issue with this type of thinking is it assumes "transport cost <<< manufacturing cost" -- a decent assumption for a lot of goods throughout a lot of history, but just... not really true for lots of things in a modern supply chain.
The cost of moving the gown between users -- in the form of the user needing to give back the gown to the service, who must then clean it, inspect it, etc. -- may in fact be far higher than the cost of manufacturing a new gown and only needing your supply lines to be "one way".
Being mindful of how much trash we produce does not necessitate producing less (or more!) -- but merely balancing the pros and cons.
They probably are fully gone now, but when I was in college some (IRL) classes, usually the big auditorium ones, added interactivity in the form of realtime polls and quizzes with a little “clicker” device. This was of course $30 or whatever and just used some custom RF protocol to register your vote across the room. Single-source, you have to buy it to be in the class.
Textbooks themselves, electronic or not, same racket. Professor is sold the book, but it’s the students who pay. (Don’t forget of course the scam of “writing your own math book” and requiring it!!)
Prisons: some private company always has a deal to “supply telephone service” and charges the inmates or their families rates that are higher than international long distance used to cost.
All of these things are sold to administrators who have no fiscal concerns with the service or product because the institution isn’t the one paying, so there’s zero pricing pressure. If there’s even multiple contractors in the niche, they are more incentivized to compete on sending cool freebies to the administrators, or add perks that benefit them, than they are to compete on pricing for the students/inmates/etc. like, say, Jostens might throw in “free school ID cards” which is technically “saving the school money” in order to get the yearbook contract, while making $100 a yearbook in gross profit on $150 yearbooks. Note: all numbers made up.