More often than not, the judges have appeared intent on raising awareness of authors who have toiled largely outside the American media marketing machine, or those who have been the victims of censorship by authoritarian governments.
Outside of Stockholm, there aren't many bookshelves loaded with the works of Mo Yan (2012 winner), Tomas Transtromer (2011), Herta Muller (2009), Jean-Marie Gustave Le Clezio (2008) and Orhan Pamuk (2006).
For example, Muller was persecuted for her criticism of Romania's communist dictatorship. According to her Nobel bio, she "was prohibited from publishing and repeatedly summoned by the Securitate for interrogations, where she was confronted with absurd accusations, reviled as a prostitute, charged with black marketeering, and threatened with death."
I find the annual awards refreshing -- a chance to discover authors from China, Turkey, Sweden and other countries. And no one would say that Munro, a master of the short story, is not worthy of the prize.
Still, I wonder if American authors are being too easily rejected. The last one to win was Toni Morrison in 1993. I wouldn't want the prizes to be based on sales alone -- sorry, John Grisham and the late Tom Clancy. But there must be a way to balance the popular and the literary, as evidenced by previous American winners such as John Steinbeck, William Faulkner and Ernest Hemingway.