Tin House, a literary magazine, asked me to introduce the current science fiction issue with an overview of the field. I wrote them an essay called "Radical Presentism," about the way that science fiction reflects the present more than the future.
Mary Shelley wasn't worried about reanimated corpses stalking Europe, but by casting a technological innovation in the starring role of Frankenstein, she was able to tap into present-day fears about technology overpowering its masters and the hubris of the inventor. Orwell didn't worry about a future dominated by the view-screens from 1984, he worried about a present in which technology was changing the balance of power, creating opportunities for the state to enforce its power over individuals at ever-more-granular levels.
Now, it's true that some writers will tell you they're extrapolating a future based on rigor and science, but they're just wrong. Karel Čapek coined the word robotto talk about the automation and dehumanization of the workplace. Asimov's robots were not supposed to be metaphors, but they sure acted