I want to believe most of what they're missing is material held in national and public university libraries and is material specific to the country the books or papers come from. Most of their collections are not digitized and that's what I keep seeing, and then some books that are profession-specific.

They're basically rebuilding Google books, and keeping it private. That's privatizing all of humanity's knowledge.

there is an amazing subplot in the book "service model" that describes a set of robot librarians doing exactly this kind of thing, plus sorting every bit.