Essentially any movie adaptation of a book can't be copyright infringement based on this being the bar; even cases that keep many lines of dialog verbatim end up just being detail similar to keeping the exact same folds of fabric at the bottom.
> Essentially any movie adaptation of a book can't be copyright infringement based on this being the bar;
I'd agree with that. A movie adaptation (with changes) should be allowed under copyright because it's clearly transformative and creative. Copyright should protect against reproduction without compensation, it shouldn't be used to prevent new artistic works from being created even when they are based on existing works. That's how I feel about it anyway, although sadly the law we have today in the US would disagree.
After all, copyright works for whole thing, not spare parts (technique, style or "idea" aren't copyrightable)...