Sometimes you feel like a rut; sometimes you don't.
There are books that are automatic. You know the characters, know how they're going to react. You know, generally, what situations they will encounter, and you know they will triumph in the end. Books of this type, when well done, are entertaining, and authors like Sue Grafton and Lee Child do well with them.
Non-automatic books take a different type of writing. The reader does not know what to expect, does not know what the characters will encounter or if they will triumph. I've just begun THE SAMURAI'S GARDEN, and it has that feel. Such books tend to be termed "literary fiction" while those above are termed "genre fiction".
I guess that's fair, but there's room for both types of writing in my life. Sometimes I want--maybe even need--to know that the story will end with the ends neatly tied up. (I didn't even mind when it seemed our hero was blown up in an underground explosion a few books back, because I knew he was going to be fine.) Sometimes, I want that edgy feeling of not knowing, of not reading the same old thing, and then I lean more to the literary side of fiction.
What I find I can no longer abide is bad writing on either side. Genre fiction that is so stereotypical or childishly drawn that it's an insult to my intelligence. Literary fiction that dresses nothing up in pretty words and expects everyone to admire it, like the Emperor's new clothes.
Writing, whatever level, whatever genre, whatever subject, has to be good writing. If a writer can entertain me with the same character doing similar things for a dozen books, good for him. If a different writer weaves a spell around me for the duration of a book, if he or she takes me deeper into the human condition, wonderful. There are a few who can do both, and those are the ones whose next book I await with anticipation. But I don't require all things of all authors. Just do what you do well, and I'll find a time when I'm in just the right mood to enjoy it.