What does a novelist owe to her readers?

Ah, Ms. Byatt, I keep reading "The Children's Book," out of loyalty and commitment to my book group, but I also keep thinking: isn't this a book in need of an editor? Or are some authors editor-proof? None would dare say this book is too long, too meandering, to sprawling. And who am I to say? The critics rave, and the book sells (reasonably) well, so she's doing something right. But there's also something wrong about a book that has no focus and no idea where it's headed. Some of the pages are almost ludicrous with the number of characters introduced, referenced, mentioned in passing. There are so many strands to the so-called plot. Yes, life has so many strands, and a novel is an encapsulated life rendered in words - the mirror held up on the highway and so forth. But doesn't a novelist owe something to her readers other than a massive brain dump? I feel as if I'm reading the notebooks of AS Byatt, and maybe I am. How would this book be if you began reading it in the middle, at a random chapter? I wonder if I would have had the same initial enthusiasm regardless of where/when I stepped in. Begin at almost any point and you'll see a good potential story, but the potential is never realized because of the abundance of her ideas and ambitions. What a peculiar book. By the way, I have to note that one thing she writes very poorly about is sex and sexuality from the hetero male POV; the guys in her sex scenes look and sound like total idiots. The scene of Philip in the brothel, with the prostitute teaching him the names of body parts in French is (unintentionally?) funny. She can write about many, many things and is hugely knowledgeable - but there are limits.