I think you folks are misinterpreting Jules Verne. They already had submarines in his time. They also had what were essentially FAX machines then, too.
Verne was a superb popularizer and extrapolator – his submarines were spacious, powered by electricity, had diving planes, and many other innovations. This put the Nautilus well ahead of the Hunley. Curiously, Verne did not predict the use of the periscope (which existed in his time) or the torpedo (the Nautilus rammed ships), even though submarines had been attacking ships with explosive charges for a century by the time he wrote.
His list of predictions is long and impressive. In Robur the Conqueror he had the heavier-than-air flying machine built out of composites (!!!). Even in the 1960s, most people didn’t properly understand what he was saying. He got the idea from the technology of his day, and properly extrapolated.
Tribulations of a Chinaman has his (Chinese) hero using a rubber suvival suit at sea.
Journey to the Center of the Earth and other novels have his heroes using electric flashlights with hand-cranked generators, like the ones I have in my house
The Barsac Mission has people calling for help using radio
Carpathian Castle has the first instrance I know of where the villain uses hidden microphones to spy on the good guys, and uses Projectors and televisions.
From the Earth to the Moon uses an aluminum space capsule for space travel (although he cheated in using a cannon for blast off), and the first record of a “count down” (although it was a “count up” – no one “counted down” to zero until the film Die Frau im Mond)
and many others.
Of course, he was frequently wrong, too. So was Wells, and so is any person who tries to extrapolate to the future. Science fiction isn’t – cannot possibly be – an infallible predictor of the future. It’s a form of popular entertainment (which might include a bit of didactic and/or social commentary) that very frequently takes the form of a story set in a future, which the storyteller has to extrapolate from his or her own knowledge and abilities. Sometimes they get it spectacularly right. Sometimes they overlook the obvious. Sometimes history takes a different turn and something that seems logical and rational never gets a chance to happen.
I don’t think we’re likely to get flying cars or rocket belts, but we’ve got the portable phones Heinlein ncasually threw into his srories. Henry Kuttner/Lewis Padgett’s movie theater-like TV sets aren’t the usual thing (although my local theater broadcasts Red Sox games onto a theater screen every summer), and almost everyone missed the real implications of widespread computers and the internet (wells’ World Mind and Murray Leinster’s “A Logic Named Joe” notwithstanding). And we aren’t in the stage of relatively easy insterplanetary travel, dammit. But a lot of other predictions have come true.
How about predicting the future? Look at what’s being written now. Will the software-enabled soldiers of the future use the things in Scalzi’s Old Man’s War? A lot of them, I’ll bet. But that’s not a tough extrapolation. Robert Forward made some hard-core science and engineering extrapolations, but they look a long way off.