Having thoroughly demolished the branch of literature I've spent forty years trying to master, let me build it up again. How can SF encourage and influence new technology?
Recall that Stephenson listed two "theories" in his essay. Hieroglyphs and Inspiration: the idea that people become interested in science and technology because of exposure to science fiction.
That is where we can shine. SF can help cultivate a mindset conducive to scientific and technical innovation, and provide a literary community for people who think that way.
Science fiction has often been derided as "power fantasy," and that's not false. A lot of fiction is power fantasy. (I personally think a better term would be "agency fantasy," but that's just me nitpicking.) Fantasy stories are power fantasies. Detective stories are power fantasies. Legal thrillers are power fantasies. Spy stories are power fantasies. Romances are power fantasies of a very specific type. All of us wish we could control more of our lives than we do, so all of us like to experience characters who have more agency than ourselves.
What's important is that science fiction is a power fantasy based explicitly on knowledge and discovery.
Way back in 1999 when the Star Wars prequel films came out, David Brin wrote a combination movie review and essay for Salon in which he contrasted the Star Wars setting with Star Trek's imaginary future. Brin maintained that the Star Trek universe is actually morally better than the "galaxy far, far away" of Star Wars.
How do you get to be a heroic Starfleet officer like Captain Kirk or Captain Picard? You study and train hard to pass the Academy's admission requirements, and then you work your butt off to graduate. How do you get to be a Jedi Knight? You're born with it.
This is possibly the most humane power fantasy possible: a fantasy of earned power, open to all. Brin claims it is fundamentally democratic as opposed to the hereditary "despotic" fantasy of being the Chosen One. (I'm not sure he's right about this; SF has an unlovely undercurrent dismissive of mere democracy, and SF writers tend to place too much trust in meritocratic elites, but that's an entirely different discussion.)
The idea of earned power in a knowable universe is what makes science fiction inspirational to techies. It isn't just "hard" SF that has this effect. Even when the science in science fiction is rubbery, it is explicitly portrayed as being knowable or at least discoverable. (Unlike the more mystical depiction of "trusting your feelings" in order to use the Force.) When science fiction characters encounter a mysterious event or situation, the story is about how they explain it. That's practically a formula of the genre: show the characters and the reader something astonishing, then pull back the curtain and explain what caused it.
The other aspect of science fiction that inspires readers is the implicit assumption that Things Will Be Different. It's hard to emphasize how important this is. Even now people tend to think that the current situation is permanent, or should be. People — including myself — have trouble mastering any technology that appears after they turn thirty or so. Science fiction reminds us that every moment is a point not on a line, but on a curve, and that things are bound to change. Because a story without any change isn't a science fiction story, after all.
This inspiration method has worked, too! Just in my lifetime I've seen being "nerdy" go from being a badge of ostracism to being a badge of defiant outsiderdom to being a form of insider. We've reached the point now where there have been some minor twitterstorms over who is a "real" nerd and who is just a poseur. Let me tell you, when I was a nerd back in 1982 there were no poseurs trying to get in with my and my friends by pretending to be interested in Dungeons & Dragons or Tron.
We see that all around us. Is it a coincidence that "geek culture" — what used to be called SF fandom — has boomed at the same time that technology has become one of our civilization's major economic engines? Techies are now high-status, and things techies like have become mainstream. The very fact that Salon gave David Brin a platform to talk about why Captain Picard kicks Luke Skywalker's ass indicates how mainstream science fiction has become, and how much science fiction has changed the intellectual and social climate.
So, to sum up: if you're looking for specific predictions of future technology, you're probably better off talking to actual technologists than science fiction writers. We're better at publicizing than we are at innovating, and our predictions are all over the map. We can't see the future.
But if you want to create fiction that will encourage people to become scientists and engineers and create the future, I think science fiction is the way to go. We can't build a better future by writing didactic stories about How It Should Be and expecting other people to do the hard work of making it happen. What we can do is write stories telling people that things will change, that the power to make those changes comes from knowledge and discovery, and that everyone can have that power.
You, sitting there reading this essay: you're one of those people. You can make the future. Don't build the future I want. Go out and build your own. I can't wait to see it.