These days you'll only find a Gatsby in films

All empires come to an end so perhaps there is nothing sad in the decline of the Brooks Brothers-wearing white Anglo-Saxon Protestant

End of an era: Tobey Maguire as Nick Carraway in The Great Gatsby, epitomises the now extinct Wasp

Baz Luhrmann has successfully managed to hack pretty much all the poetry and beauty of F Scott Fitzgerald's prose out of his new version of The Great Gatsby. He has, though, maxed up the 1920s Wasp (white Anglo-Saxon Protestant) chic. The film's costume designer, Catherine Martin, has really gone to town, basing the 500-piece wardrobe on 1920s catalogues for Brooks Brothers, outfitter of choice to Jazz Age Wasps, Fitzgerald included. The Brooks Brothers flagship shop on Madison Avenue, and its global outlets, are also going Wasp crazy – offering Gatsby's bow tie, Nick Carraway's green, shawl-collar sweater, boaters and blazers.

With the return of Gatsby style, you could be forgiven for thinking the Wasp is alive and kicking – or should that be buzzing?

But these are just flashes of nostalgia for an era that, in all its other meaningful incarnations, has completely disappeared. The Gilded Age – Mark Twain's expression for the days when Wasps ran America – is long gone. The Wasp is dead.

In 2010, the last Wasp on the Supreme Court, John Paul Stevens, then aged 90, retired. Among the directors of New York's Metropolitan Opera, once dominated by Wasps, there isn't a single surname Edith Wharton would register.

The old Wasp fortunes – founded in steel, oil, banking, railways and textiles – are now dwarfed by tech fortunes built up by the likes of Steve Jobs and Mark Zuckerberg. Charity boards necessarily recruit from the ranks of the new rich, with growing cash piles and a fresh desire to give away their money.

Throughout the upper echelons of American life, it's bye-bye to the Wasp – and the Waspess – with their strong affections for Britain, old-fashioned style and high European culture. Enter a new American elite with no particular attachment to American history, to Anglo-European culture, to the old Wasp palette of interests and habits.

Wasps were distinctly American, despite their European and British roots. The new American movers and shakers aren't recognisably American at all. They look much like the international global elite, slipping comfortably and invisibly into the gilded crowd in upmarket bars, restaurants and drawing rooms across Britain and Europe.

On election night in New York last autumn, I went from the party held by the conservative cultural magazine The New Criterion, in Tribeca, to one held by the liberal online magazine Slate, in SoHo. The 10-block journey between the two was a power walk from the American past into the American future.

The New Criterion party was filled mostly with men in their forties and fifties, largely dressed in suits, still with that vigorous interest in Western European high culture. At the Slate party, the guests were in their twenties and thirties, dressed down, with more young women and a jazz-soul band. At the New Criterion party, the results were broadcast on a single television screen, while we drank white wine and ate freshly prepared canapés. Up in SoHo, we drank beer as we consulted banks of computer terminals for Nate Silver's latest predictions.

The election results slammed the last nails into the Wasp coffin, even if Mitt Romney was really a Wasm – a white Anglo-Saxon Mormon. The majority of whites may have voted for Romney but, in an age of white population decline, that wasn't enough for a Wasm victory. Among American voters earning more than $50,000, the majority also voted for Romney – and in increasing proportions, as the wage bands rose. But that, too, made little difference to the result: the professional Wasp vote is increasingly inconsequential.

Originally, "Wasp" was only used for the rich, particularly the Eastern Seaboard, F Scott Fitzgerald type with crumpled, button-down collars and Ivy League degrees. Andrew Hacker, first to use the term in print in 1957, said Wasps "are wealthy, they are Anglo-Saxon in origin, and they are Protestants (and disproportionately Episcopalian)".

As the election results showed, those rich Wasps are a race in retreat. But it's worth remembering there are millions of other Wasps – that is, in the word's looser, less preppy sense, meaning white Anglo-Saxon Protestants of all classes and salaries. There are still more of these Wasps than any other individual ethnic and religious group in America. But the death knell has rung, too, for their old Wasp values.

Even in areas where those poorer Wasps are still in the majority, Wasp confidence in its own culture is disappearing. Until the 1960s, you didn't even have to be a Wasp for the Wasp view of history to be the one you were taught at school and university. The story of America, then, was the story of the white Anglo-Saxon Protestant: from the Pilgrim Fathers to the Founding Fathers of the American Revolution, to the Yankees and Confederates of the Civil War.

These days, the traditional teaching of the Waspish, Western European canon has given way to multiculturalism and relativism. There is now no central, generally shared core of historical knowledge. It is every man for himself – or for his own version of history, individually catered to his own background.

"Immigrants actually want to learn an elevated Western culture, but they're not being offered it," says Melik Kaylan, a Turkish-born journalist in New York, who writes about culture for The Wall Street Journal. "Conservatives haven't staked out their cultural place in America, while the left has. The surviving fragments of Wasps have self-ghettoised and marginalised themselves. They have become ironic and self-conscious about their culture. There has been a self-betrayal by the educated classes.

"There's no such thing as an elite culture to aspire to any more in America," Kaylan continues. "It used to be the case that the new rich – like Henry Clay Frick, who built New York's Frick Collection – would embed themselves in the canon of Western European art. Now the new rich feel no need to be educated. They just retain their adolescent enthusiasms, like Paul Allen [Microsoft's co-founder] and his obsession with Jimi Hendrix guitars.

"Republicans are the same as Democrats: they have the same dismissive attitude to high culture. That internal, proud, cultural American identity was swept away progressively from the 1960s to the 1990s. American culture may be stretched widely across the whole world, but it is extremely thin."

The old Wasp writers are dropping like flies. Kurt Vonnegut died in 2007. John Updike went in 2009. The tragic arc of Updike's most famous character – Harry "Rabbit" Angstrom, the high-school basketball star who rebels against middle-class, suburban American life, ending up with a drunken wife and a drug addict son – moved in lockstep with the fall of the Wasp.

It's striking that the last great Wasp novelist, Tom Wolfe, now 81, turned to the new America for his latest novel, Back to Blood; setting it in Miami, the most mixed city in the country, where Anglos – as Wasps are called there – are down to 10 per cent of the population.

All empires must come to an end, and perhaps there's nothing sad in the inevitability of decline. But, still, it's worth calling attention to the structural sea change in the world's richest, most powerful country.

How the last line of The Great Gatsby must resonate with the last Wasps, as they sail into the sunset off Martha's Vineyard: "So we beat on, boats against the current, borne back ceaselessly into the past."

Harry Mount's How England Made the English (Viking) is out now in paperback