One lecturer actually had notes on their slides for the differences between the latest version of the course book and the one before it, since the latest one wasn’t available for free anywhere but they wanted to use couple chapters from the new book (they scanned and distributed the relevant parts themself)
Tbh they already do everything they can, if you ever need a paper, e-mail the author and they’ll most likely send you the “last version” before publication they still hold the rights to distribute