At my college, at least, we're very undergrad-focused. So the professors tend to request things that are good for those sorts of classes. There's about 3,700 academic libraries in the USA.

We also subscribe to some large collections of ebooks, which we don't individually curate. We have the ability to add on individual books to our ebook collection, but most come in, say, the EBSCOhost eBooks Academic Subscription Collection. I have Opinions about ebooks vs physical books in a library setting (mostly, I don't like renting books and prefer something a publisher can't take away on a whim). But ebooks sure are convenient for students, especially if they're taking classes remotely. COVID was a push towards ebooks.

Mini rant: our physical book collection needs weeding, but we don't have the budget we'd like for new books. Whenever I pull together a display for, say, LGBTQ Pride, I have to decide whether to include a copy of "Poetry of Sappho" from the 1930s that looks like it's from the 1930s[derogatory]--no dust cover, just blue paperboard. No young adult's going to walk by a worn blue rectangle and say "yes, I want to pick that up and read it".

I want to put together an attractive display and a lot of my options are ugly.

And weeding's complicated, too. You can't just say "oh, this is 30 years old, get rid of it". That tends to work in Science/Tech/Medicine, but a 30-year-old biography might be the only one written on a person. Is there a newer one we should get? Is the older one bad for some irredeemable way, or is it bad in an interesting way? (example: written by someone super biased in favor of the subject, but the author's biases are intriguing, or they're the only biographer to actually talk to the subject, that sort of thing)