An instant and obvious good these companies could do is to digitize these books ala google books.

And get sued even harder by publishers?

Publishing any out-of-copyright books would be awesome thing to do. But it seems none of the books in this order would fall under that, and it's unclear how many old books they are actually ingesting. Current reports are mostly talking about relatively recent books

Preservation rather than ingesting them into the gaping maw of an Intelligence Engine that preserves the soul of the book in crystalized neural network form? That would be a copyright violation.

Then they would have to deal with copyright. AI is the washing machine that leaves everything spotless.