Am I saying you have things backwards? Well maybe not quite. But supposing what you think is forwards is less interesting than what you think is backwards? In the novel you describe Stephen King presents a writer shocked into a writing block by his wife's death and his inability to grieve. I agree this part of the book is pretty good, and so is all the legal stuff about child custody, and how those seedy arguments are constructed and conducted. But this is just a novel, not a genre novel. It doesn't tell us anything about genre at all, except perhaps that you think King should get out of it. What I see in Bag of Bones is a haunted house story fuelled by the writing block material, but needing the genre to get it off the naturalistic ground.
The fuel is fine, but it isn't the genre. And I do think that all talk of the organic in writing has some romantic mythology of the artist in its train, some inspired or not inspired individual lurking in the basement. Whereas I believe the great dreads are shared dreads, not the result of a personal communication, however authentic, from Our Author.
Hey, maybe we're having an argument.