Disney lawyers are using an arbitration clause in their Disney account agreement to try to dismiss a lawsuit over a death caused by allergies at Raglan Road. You should be able to find the articles from there.
It's a bit simplistic to say that it's specifically a Disney+ issues.
I prefer 720, both for file/bandwidth reasons and for quality reasons. Once you start getting into higher quality, it starts looking like you're actually there in the room with the actors, and I don't like that. It's unsettling. I want my TV and movies to look like TV and movies.
I don't think books were copyrighted back then.