Which can be an issue for films. The film I mentioned (Fireball) the little girl in it was essentially a McGuffin to hang a villainous villain and lots of explosions and fires on. I'd imagine that felt like a kick in the teeth to a writer who's spent a long time developing the character over however many hundreds of pages.
I can imagine The Stand working. If the film is good and marketed very well with a big hitter or two in the cast then the source material is pretty much irrelevant to the majority and would pull in King fans on top of that.
Spot on.
I can imagine a good percentage of the audience for the re boot of Dune, had never seen the original or read the book, but if you make the film that good and get your marketing right ( which they did ) and then the film sells itself ( which it did )