>Copyright law tolerates lending by libraries in the case of print books because those books eventually wear out.
I don't think this is entirely accurate when it comes to copyright law. The law extends back centuries and digital books only appeared within the last couple of decades. The ability to lend a book (by libraries or any owner) without committing copyright infringement is much more closely-related to the first sale doctrine (which has been around for at least a century in U.S. law in one form or another) than it is to a book's durability or lack thereof. Recall what the opinion says about the underlying rationale for copyright law: let the authors have a period of monopoly so they'll have an incentive to keep writing. If the first sale doctrine doesn't defeat that rationale in the case of print books then the same logic should apply to digital copies; it's the first sale that matters, not how many times the owner of an individual book can then lend that book to someone else. Granted, as in your second point, publishers can limit lending of digital books through license agreements or other digital rights management, but at that point you're in the realm of contract law, not just copyright.
I don't think this is entirely accurate when it comes to copyright law. The law extends back centuries and digital books only appeared within the last couple of decades. The ability to lend a book (by libraries or any owner) without committing copyright infringement is much more closely-related to the first sale doctrine (which has been around for at least a century in U.S. law in one form or another) than it is to a book's durability or lack thereof. Recall what the opinion says about the underlying rationale for copyright law: let the authors have a period of monopoly so they'll have an incentive to keep writing. If the first sale doctrine doesn't defeat that rationale in the case of print books then the same logic should apply to digital copies; it's the first sale that matters, not how many times the owner of an individual book can then lend that book to someone else. Granted, as in your second point, publishers can limit lending of digital books through license agreements or other digital rights management, but at that point you're in the realm of contract law, not just copyright.