Eudora Welty and Southern writers

I found this interesting article about Eudora Welty in The New York Times. As well as talking about her life, her works, awards, etc... one particular paragraph caught my attention:

For decades she was pigeonholed by critics who placed her with William Faulkner, Katherine Anne Porter, Flannery O'Connor and Carson McCullers as a writer of the so-called Southern School. Her reputation as a regional and apolitical writer was often cited as a reason for her failure to win a Nobel Prize. But her work, like that of those other Southern writers, transcended region and possessed a universal relevance and appeal.

I've heard this said before -- that regional writers don't get as much respect as national (or global?) writers. What do you think? Does being classified as "Southern" hurt a writer? Does it limit his/her success? I'm thinking of NC authors Lee Smith and Jill McCorkle in particular -- being Southern doesn't seem to have hurt their careers. But what does everyone else think?