Most of the Internet Archive/Archive dot org/Wayback Machine "Open Library" is pirated copies, some even scanned by them. Their (mostly) Public Domain works are available directly on the site. Also a lot of their content is OCRed Scans/PDFs. Proper PD sources proofread the text and supply real ebooks, such as the library here or
www.gutenberg.org and anything else you need to buy a copy. A few indie publishers include a free ebook download if you buy their paperback. All publishers should do it.
DRM is nothing to do with Copyright. Not really, DRM is about control. Some PD works are distributed with DRM and many copyright works can be bought without DRM.