Agree with you on what we should represent as a software library. People tend to search and query for pockets of information in a library. Libraries tend to index and organise to make this easier. Libraries also tend to manage versions (aka editions) of this information. Where as individual packages manage isolated pieces of information; there can be a version set on them but they are unaware of other versions much like a book
However, in terms of calling individual bundle of information, books, might be a hard sell for everyone accustomed to what a book represents. Term which is rarely used in the context of a software system (maybe in accounting ledger-like systems). Book is a series of information bound by the context, a story, its trying to convey. Which is exactly what an individual package represents. Book is a package and that makes sense, going back in time, throwing weight on calling a package/bundle a book might have held well.
As you've mentioned, two other common terms are package and a bundle. So one way I could see myself looking at this is: a library, such as NPM/apt, contains packages, and a package is a book or a collection of associated books.
Makes me think how human speech would change overtime both by trying to counteract AI learning from us by using garbled speech. And optimised to try and squeeze out what we want from it the quickest.