A science fiction short story by William Gibson, copyright 1981 by Terry Carr, first published in Universe 11.
Our protagonist is a photographer employed by Dialta Downes, a British pop art historian obsessed “with the more baroque elements of American pop culture”. Downes is writing a book, The Airstream Futuropolis: The Tomorrow That Never Was, about a style of architecture she calls the “American Streamlined Moderne”. She wants him to go out to California and photograph the quirky architecture of fluted aluminium dime-store facades, gas stations seemingly designed by Ming the Merciless, cinemas that look “like the temples of some lost sect that worshiped blue mirrors and geometry”.
So our protagonist goes out and begins to photograph what Downes described as traces of an alternate reality where the covers of Gernsback pulps were true and blond-haired-and-blue-eyed Americans drove in shark-fin roadsters between cities of chrome and crystal - the Gernsback Continuum. As he does so he begins to ponder what stopped our continuum from becoming Gernsback Continuum - foreign wars which it was possible to lose, rockets that went down instead of up, fumes from cars that had no wings that blackened the crystal spires of the futuropolis - and, very gently, he goes over the Edge.
Haunted by twelve-engine flying wing airliners (two squash courts, a ballroom, New York to London in two days), he drives to Arizona on roads that sometimes split into forty lane elevated origami highways to meet Merv Kihn, cynic and expert on UFO nuts, cultists, etc.
Kihn explains that the protagonist has seen a semiotic ghost, a piece of cultural imagery that has taken a life of its own. He connects this with UFO sightings and devil sightings in the Middle Ages saying that they are just different interpretations of semiotic ghosts. Though this is as good an explanation as any, our protagonist is not satisfied and heads back for L.A.
Stopping somewhere in the midnight desert, exhausted after hours of driving, he falls into a fitful sleep (sound portentous?) and awakes to see, in the distance, a huge city of spires and ziggurats, thronging with blimps, gyrocopters, flying wings. Then, ahead of him he sees them. A perfect pair of Aryan Americans with their car, an “aluminium avocado with a central shark-fin rudder jutting up from its spine.” The city is a dream version of Tucson, and these were the children of the Gernsback Continuum. Our protagonist finds it disturbing, and so do we - “It had all the sinister fruitiness of Hitler Youth propaganda.”.
He gives in to Kihn’s theory of semiotic phantoms and calls him and asks how to get rid of them. It turns out the way to exorcize semiotic ghosts is to immerse yourself in our near dystopia reality. The close of the story sees our hero buying an armful of newspapers on the petroleum crisis and the nuclear energy crisis.
“Hell of a world we live in, huh?” Says the newspaper vendor. “But it could be worse , huh?”
“That‘s right,” Our protagonist says “or even worse, it could be perfect.”