There are many writers who deserved the Nobel prize but never received it. Joyce, Kafka, Borges, Proust, Tolstoy, to name a few. The prize has been so consistently politicized over the years that it's hard to see it as a measure of much of anything other than how much a bunch of Swedish academics happen to like that author.

If it were up to me I might pick Thomas Pynchon or Cormac McCarthy over DeLillo for a Nobel prize, but there are many other worthy non-American candidates