I worked at the library at a university library for a while. I hadn't heard about the issues you mentioned, but the issue of this article was very common.
It stemmed from our lending policy. Undergrads could get a book for two weeks, but had a two-week grace period on renewals (sorta weird). Grad students and professors could check out books for the entire academic year, they were supposed to physically bring in their books for renewal once a year, but many times they could convince staff to just renew all books on their accounts. Some professors had over 100 books checked out and many didn't know how many they had checked out. The common response to inquiries was to tell the student to go talk to the professor. We were allowed to give out professors names.
At my university, there was 3 day lending policy. With renewals within the day of return. Due to a limited selection, it was possible for others to put a 'hold' on it. This means library staff would keep it behind counter for up to a week before releasing it to the next hold request or put it back on shelf.
Since some undergrad books were in heavy demand (especially due to assignments/exams) when it's common to see holds. Some students have learnt to put the book somewhere else in the library so they could have exclusive privilege of reading it.
Conversely, I haven't heard of the professors or anyone hoarding lent books. All holds I have placed eventually turned up available in <3 days. Your two weeks policy is very generous and something I would have liked over 3 days which seems quick.
It stemmed from our lending policy. Undergrads could get a book for two weeks, but had a two-week grace period on renewals (sorta weird). Grad students and professors could check out books for the entire academic year, they were supposed to physically bring in their books for renewal once a year, but many times they could convince staff to just renew all books on their accounts. Some professors had over 100 books checked out and many didn't know how many they had checked out. The common response to inquiries was to tell the student to go talk to the professor. We were allowed to give out professors names.