Intellectual property owners care about your license.
They don't care where you get your physical copy of the IP.
Suppose you're a bar owner, and you obey the law and get an annual ASCAP license. You can now play any ASCAP music you please in your bar, all the live long day. Note that the license does not come with a USB stick of every ASCAP song; you must still obtain the songs on your own. Nobody cares where you source your physical copy of the media. If you want to rip it from friends' CDs, trade AAC files, or leech it all off BitTorrent, have a field day.
Exactly the same applies here. Drop the book in a plastic bag while still at the library - this gives you a proper license to have the IP. Now, move it to somewhere it won't get destroyed -- and while it's in your control, BitTorrent or otherwise "obtain" an ebook file of the book. Enjoy it, delete the digital copy, and then return the physical book. Still in the plastic bag.
Do not extrapolate this into "borrow the book, pirate the audiobook" - those are different IPs.
Libraries have looked at delivering obscure books this way for many years - when a Web visitor wants to read a book, you "check it out" in the system meaning no one else can use it; then let them securely see pages at their pace; and after they logout or timeout, "check it back in" so it's available for virtual or physical checkout. (or simply outlaw ALL physical checkout, so the paper book remains in cold storage forever).