Garth Risk Hallberg from the Millions asks if big books are back in, as we ride out the aftershocks of gigantic tomes like Joshua Cohen's Witz (800 pages) Jonathan Franzen's Freedom (576), Rick Moody's Four Fingers of Death (725), and the continued popularity of backlist doorstoppers like Infinite Jest (1104), 2066 (912), and Imperial (1344). This goes against the popular argument that people won't read anything longer than a "Jersey Shore" synopsis anymore.
Beyond the simple economic explanation that readers want more bang for the buck when they buy a book (imagine if bookstores advertised price per page like grocery stores sell by the ounce), Hallberg says the popularity of big books stems from a committment by a certain type of reader:
For a deeper explanation of the long novel’s enduring health, we have to look toward something harder to quantify: the construction of the reader. The more we’re told we’re becoming readers of blogs, of texts, of tweets, of files the more committing to a big book feels like an act of resistance. To pick up a novel in excess of 600 pages is to tell oneself, “I am going to spend twenty-four to forty-eight hours of my life with a book, rather than the newspaper, the internet, or the smartphone. I am going to feel it in my muscles."
To take that argument further, I'd say that the type of poeple who still read books of any kind are less likely to be scared away by page count, and if they are going to commit to 600+ pages, it had better be good too.