My first thought is how accessible these books are. If a book hasn't been checked out in years, and there's another library in the interlibrary loan network that has a copy, there's no practical reason to keep another copy. If you can request a book and have it arrive in a few days, that's not an issue in any real sense, especially for books that nobody is checking out in the first place.
I used to work in a library, and this was often the case. Our basement was stuffed to the gills with romance novels that nobody was reading anymore, mysteries published decades ago, and kids books that probably related to kids from a previous generation more. A yearly sale would see the collection trimmed. Almost across the board, you could still get those books through interlibrary loan. If not from the county network, from another library in the state. In my time, I never heard of anyone missing a book that had been disposed of.
I used to work in a library, and this was often the case. Our basement was stuffed to the gills with romance novels that nobody was reading anymore, mysteries published decades ago, and kids books that probably related to kids from a previous generation more. A yearly sale would see the collection trimmed. Almost across the board, you could still get those books through interlibrary loan. If not from the county network, from another library in the state. In my time, I never heard of anyone missing a book that had been disposed of.