First, to be clear, I work for Amazon, and I don't work on this or related efforts, I am a security engineer. I also won't talk about or answer questions at work, and my comments are more generally about the practice (all of the major organizations building AI are doing destructive book scanning). These are my opinions, and do not reflect my employers (past or present).
You might be right that they can't do that now. The simple path forward is to have these companies simply make a public commitment to publish the data when the copyright expires. I also think there is a space to be carved out, probably through regulation, to ensure that there is a clear path for these scans to enter the public domain, at the very least.
This is not just important for these specific books, I have written on other platforms and in other spaces about the importance of media companies and those who benefit from strong copyright laws to protect and generate profits and revenues to repay the public for the cost of that enforcement over time by ensuring that at the appropriate time, those works fully enter the public domain. That could mean a restructuring of the Library of Congress in the United States to become a modern Library of Alexandria to host data, and shifting to a registered copyright model where to gain the protections of the court, you need to upload/submit your copyrighted works for storage and eventual release. I doubt it would ever happen there because of the amount of money invested in tying up IP in the United States, but perhaps a more amenable location like the EU could help with that.
However it might work, part of the promise of the Internet was that information would be liberated, but we see every day how much information gets sent down the memory hole when businesses, sites or services shut down, or how regularly companies abuse IP related regulations to attempt to strangle competition. It would be expensive now, but it would create an incredibly valuable legacy of information for the future, and it will only get more expensive to build such a thing as time goes on.
