The problem with changing the world that was created by a writer is that the world had become so popular for a good reason.
I didn't read Dune nor Brave New World, but I loved the Dune movie and didn't enjoy Brave New World series, because it just didn't make sense. I love exact book adaptations even if I hadn't read the book.
Another issue is that whoever they're hiring to write these adaptations either have no clue how to write, or are hamstrung by committee direction. You can make, quite effectively in fact, a story set in the same universe (cue all the Star Wars material that exists as books in the fandom) that has nothing to do with the original story. But it needs skill. Skill that they cannot seem to find.
I didn't read Dune nor Brave New World, but I loved the Dune movie and didn't enjoy Brave New World series, because it just didn't make sense. I love exact book adaptations even if I hadn't read the book.