Like, there was some of that when I was an undergrad 20 years ago, I certainly sold back some of my books. But ebooks and book rentals weren't as much of a thing, certainly not this current trend of "affordable access" publishers are doing where you pay a monthly fee for access and then when you stop paying the fee you lose access to that resource. And it just makes me really sad that students today are unable to hang onto useful course materials like I was able to.