> You think someone's picking up a first edition Steinbeck and destroying it so it gets into the next training corpus?

I doubt the low-paid workers stripping, scanning and shredding the books are checking what anything is. I'd imagine they are dumped with a big crate of old books and an hourly quota they have to rapidly process.

Arguably old technical manuals with limited print runs are even rarer or more valuable to historians. We have lots of copies of Steinbeck, albeit not first editions.