In general, I think that advice is sound. Faulkner is the greatest because he imbues his small, Southern universe with universal humanity. Steinbeck does the same with rural California. Joyce with catholic Ireland. And so on.
But it seems that modern American "high literature" is much more narrow than that of the past. Instead of taking the reader to rural California, fictional Mississippi, or the depressing Pacific Northwest (Carver), the reader always ends up in either New York City or a college English professor's office. The universe of settings and motifs has seemed to shrink, not expand, with globalization. Part of me thinks this has to do with the "write what you know" commandment. If all American writers today are university professors or New York City residents, what else can they write about? Maybe we need to find ways to support writers who have jobs other than pointy-nosed professor or Brooklyn hipster.

I, like Tucker, am somewhat ambivalent about Jonathan Franzen's Freedom. Part of my ambivalence is that the book, while very not short, seems narrow in its impact. It doesn't touch the pulse of the country in the same way that Faulkner or Steinbeck do. The book reveals much about modern life in NYC, but maybe not as much outside of it. Even though half of the book is set in Minnesota, is seems that the denizens of that frozen tundra are really NYC residents - they just don't know it yet.

I'd love suggestions on new (last decade) American literature that breaks with the academic NYC mold. My personal favorite is Marilyn Robinson who writes about small-town midwestern women. But Marilyn doesn't exactly break the mold - she's a professor at Iowa.