I just started (and stopped) reading The Way of Kings by Brandon Sanderson. I was a bit taken aback when Part 1 was given to me as two large books, but I thought, OK, what the hell. Then I was told that it's supposed to be a ten-part series, and that's when I thought "fuck this" and stopped reading.
It's not that it's badly written; in fact I've found what I've read so far moderately entertaining. However, I want to be able to get some resolution to a story within my lifetime.
Once upon a time, I could pick up a novel and finish it in an afternoon; I could take a chance on an unknown author because I didn't have to invest years of my life to find out if they could write a decent story or not. Many years ago I got a summer student job at a public library, where my duties were basically non-existent and I spent my time reading my way through their entire fantasy and science fiction collection. I could do that, and be exposed to a whole lot of authors I'd never heard of before, because they weren't all writing multi-volume epic sagas padded out to tell a basic tale in as many over-bloated marketable pieces as possible.
Things have come to a pretty pass when an author can't construct a publishable tale within the space of 150 or 200 pages, and when what used to be novel-length is now a short story. If you're taking a novel out beyond a thousand pages, you'd better have a fucking good excuse for it, and be telling a story that will have as great an impact on me as The Lord of the Rings did. Otherwise you're just wasting my time, and wasting perfectly good paper and ink.
Now, I have no objection whatever to an author milking an interesting milieu or re-using interesting characters. A series of stories set in the same world is just fine and dandy, and I've enjoyed several authors who do (or did) just that. What I object to is the currently very fashionable idea in fantasy and science fiction publishing that page quantity is more important than story quality.
In fact, I've come to object to it so strongly that I'm just not even going to look at books published in such a fashion any more. Fuck it.
I strongly suspect it's all another facet of the "re-make, reboot" model that infests the film industry, where the only way to get something made is for it to have already been made (and successful). The studios and publishing houses aren't really interested in originality; in fact, they appear to be actively discouraging it. They don't want something new, they want something safe.