>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.
These libraries do not coordinate the deaccessioning. If it ever gets down to 2 copies, there's a non-zero chance that they will deaccession their copies simultaneously, and then there are none.
You worked for a library. Did they ever check first to make sure some other library had a copy? Did they warn that other library "we're getting rid of ours, please don't get rid of yours"?
These libraries do not coordinate the deaccessioning. If it ever gets down to 2 copies, there's a non-zero chance that they will deaccession their copies simultaneously, and then there are none.
You worked for a library. Did they ever check first to make sure some other library had a copy? Did they warn that other library "we're getting rid of ours, please don't get rid of yours"?