But to publishers, increasing the volume of printed copies of a given title is absolutely not equal to a library purchasing a single copy and physically handling it in circulation until it naturally degrades to the point of being trashed. Physically printing brand new copies for patrons to keep every time a book was 'checked-out' would pose such a materially large impact on sales volume that publishers flat out wouldn't allow it.
Even a perpetual license to loan a single copy of an ebook can cost a library upwards of $100[1], due to potential revenue impact to publishers/authors from having it in circulation in perpetuity without physical deterioration naturally limiting it's lifetime/volume of loans. And the number of simultaneous loans for a given title is generally restricted to the number of individual licenses you've paid for. If that's the case even for ebooks, you can imagine what they'd require to print a title on demand and give it away to a patron forever.
[1] https://www.authorsguild.org/industry-advocacy/a-new-twist-i...
Sounds like it’s not that far from a point where it’d be cheaper to just print a book on demand, mail it, and tell ‘em to just keep it or pass it on.