I think Mr. Greco is right. Even when you scan a book, sometimes scanning isn't perfect. If the publisher produced an accessible version to begin with, that would alleviate that problem. It would alleviate the need to spend time scanning, and it would presumably produce a better copy. After all, as far as I understand most documents these days started out electronically, so I see no reason why an accessible version in an electronic format can't be produced.
On October 22nd, 2018. See this statement in context.