I think one of the issues with ‘future tech’ is that we’ve gotten to the point where we hit an analogy to the alien life dilemma (either it’s there but it’s too far away to get in contact with, or it’s not there, so why worry about it?), with an added twist: alien life is already here.
Basically if you think of flying cars.. we know they can be done, but the regulation, severity of incidents, etc. would be a nightmare. We’d want them to autonomously fly-by-wire all nicely first, and before we go there, we need to do so on the ground first. That was ‘future tech’ 20 years ago, now Google’s experiment is showing that it can and does work.
Not too long ago, replicators also seemed like science fiction. Nowadays, not only can you have 3D objects printed in a variety of materials, but for less than $500 you can have a 3D printer on your own desk. Sure, it’s not quite like a resequencing of base material atoms into spacebooze, but between that and 3D printed organs we’re making great strides. It’s rapidly becoming less fiction and more fact.
Now take something like a holodeck, though. We can imagine all sorts of display technology, but scientists have no clue how to create a virtual object in mid-air that isn’t also translucent and/or luminescent (projecting onto smoke/mist/dust particles, or by igniting the air itself into a plasma), never mind giving tactile feedback. A VR helmet and force feedback gloves are as close as you’re going to get for the foreseeable future. So it’s relegated to purely science fiction until somebody comes up with a feasible way to actually make this happen, and that might require a revolutionary new discovery first – which tend not to happen very often – or a completely different approach (rather than actually having a world created around you, just make the brain think there is). Until then, it’s not really something people tend to think about nearly as much as flying cars were on people’s mind a few decades ago, because it really does seem outside the realm of the possible – whereas flying cars have been known to be possible (remember the car that you’d just bolt wings onto?). It seems less science (fiction/fact) and more magic, and ‘any sufficiently advanced technology …’ is only going to apply, and immediately self-destruct, when it’s become reality.
If instead you think of a portable computer that you carry in a pocket and allows you to look up information no matter where you are.. well, we’ve already got that. The ability to take a photo and show it to your family half way across the world immediately? We’re there. Create diamonds out of carbon dust? Been there, done that. Fly from Paris to New York in just a few hours? Had that, no longer have it, but we know it’s possible at least and might be getting back to it.
tl;dr: The future is now, and we’re generally far too cynical about the future-future to regain the euphoria of decades past. But there will always be people imagining new things, and people trying to make them a reality.
On the up side, you can at least find remote controlled flying cars, like the B (no endorsement, just coincidental recent launch).