If the serialized one is in the public domain and a book isn't, then your work might be seen as derivative of the book anyway.

For instance the recent Wicked movie (and book, and play, etc) can't use ruby red slippers, because that was a detail only in the relativley more recent movie, so even though the original wizard of oz book has been in the public domain a while, some details are siloed off. I think the Holmes stories had disputes like this for a while too, where if you mentioned certain side characters it might infringe a more recent adaptation or etc.

The Holmes situation was even sillier than that: they were arguing that certain personality traits of Sherlock were still under copyright: https://www.denofgeek.com/movies/conan-doyle-estate-sues-net...

I can see how having the public domain source material might be necessary to defend yourself against claims of infringement of the non-public domain works. That makes sense to me.

What if you just want to read something without a credit card? In the far-off past, it was once normal to buy a book without your purchase registering in dozens of databases, being cross-referenced with your electricity bills and the people you went to high school with, then analyzed for your marketing or terrorist potential. You would go to a bookstore, hand them something called cash, they would give you a book, and your relationship would end.

Now you can only do this through piracy.

I'm honestly not worried about getting zoomer takes on Red Harvest. I'd like to be able to legally send it to somebody I recommend it to without involving hundreds, if not thousands, of other people.

Secondhand bookstores still exist. I’ve found first editions at them before, so that might not be a bad place to look, actually.