Destructively scanning books is the most financially effective ways to scan books. I remember there use to be companies that'd destructively scan college textbooks and give you back a PDF. Ebooks would be the most efficient, but I can't blame them if they have to buy a physical book to buy a license to content and avoid some EULA that'd restrict them beyond standard fair use (there's been some court cases saying scanning books you own is fair use, including one by Google AFAIK).

I'd say blame Amazon for their eula, as opposed to anyone for buying a physical print than destroying it to have a legal digital copy that doesn't have additional restrictions beyond standard copyright law.