I think George Saunders hasn’t written a novel because he’s too much of a prose perfectionist. Because he’s unwilling to write a mediocre page. Because he likes the control the short-story form gives him.
“A novel is a work of a certain length that is somehow flawed,” a wise critic once said — and as I was told during the first few weeks of my MFA program.
To write a novel, and see to it through from the first word to the 150,000th, you have to be willing to embrace the idea that every once in a while your prose is going to be, for lack of a better word, more prosaic than it would be otherwise. Why? Because to get a reader to make it through 150,000 words (the length of my last, and about the length of your average robust novel), you need this clunky, unattractive but very utilitarian thing called a plot.
The Remainder Table
Theryn Fleming
The Remainder Table 
Hell … why is 150,000 words the target? Particularly these days with the flexibility offered by e-publishing. More and more great stories are on the shorter end of the novel spectrum than the longer. Who knew a novel had to be 500 pages long.
That was just an example. The point was that writing a longer work requires a writer to give up some of the control they have when writing shorter pieces, which is hard for perfectionists.
I know, I know. Just seems to me that somebody who feels like a novel needs to be 150,000 words needs an editor. 🙂 There is definitely something to be said for a longer story giving you more freedom to not worry about every word. I think plot and the other elements of a story become more important with long stories.