* Given an annually compounding 30% linkrot, 99.92% of all the content ever published on the Internet is no longer available.
* This has been litigated, see Field v. Google Inc., 412 F (2006), and held to be "fair use" due to safe harbor of Section 512(b) of the DMCA
* This exemption does not apply to books, music, videos, or any of the other pirated material.
The IA doesn't appear to buy many books or CDs or DVDs (it has donation drives for second-hand copies). It doesn't do any controls over the number of copies "out". It resembles MegaUpload or other piracy sites more than a library.
This is untrue; under normal circumstances it had matching numbers "out" in the commercial book collection. It was madness in early 2020 when they temporarily abandoned this control in response to COVID.
https://archive.org/details/statisticaltherm0000stid/page/n4...
You can look at a few pages of this book; you can log in and check it out, if no one else has it.