What were the tech trends thought to be revolutionary but died out?

Shareware - Back when we had the relative safety of hardware too dumb to stuff trojan horses in, and write protectable operating system disks, it was commonplace to have a vendor at your local user group with floppy diskettes full of new stuff to try out, for $2-3 per disk. There are thousands of disks with dozens of programs on each.

This was mobile code on a scale that is currently impossible. Once we get capability based security that protects the hardware and our data from things we run by default, it's possible it'll make a comeback, and there will be another wild explosion of creativity in programming.

Wearable computers were going to be a thing several times - look at the progression of Prof. Steve Mann's wearables[1], around the late 1990s when the Twiddler chording keyboard he's using became available and the hardware was small and light enough to be more like a big walkie talkie than a freakshow. Again with Timex Datalink watches, and things like PDAs and Palm Treos, again with Google Glass, again with early smartwatches. They were basically all wiped out by smartphones. Maybe smartwatches are in fashion again now, but maybe not.

Netbooks - the idea of a low power device which can hardly do anything. From the Asus EEE to the WebOS tablet to the One Laptop Per Child to the Chromebook. You could say the Chromebook did become the next big thing, but it's kinda been trumped by the Macbook M1 which has smallness, battery life and none of the web-only restrictions, and competing on price was always a struggle between the low-end Windows laptops and the high prices of decent Chromebook hardware. On the low-price end, Raspberry Pi came out.

Airships, they were going to be the great military air power of the WWI era but too many crashed, they were going to be the long-distance passenger and freight vehicles of the pre-WWII era, but the Hindenburg and other accidents happened, they have been going to be reinvented by Airlander (2001), Techsphere (2003), DARPA / Aeroscraft /Lockheed Martin (2009), similar work by Google Loon (2011 - 2021), Airlander with Graphene (2016), Airship do Brasil (2017), Buoyant.aero (YC 2019?), SkyCat, among others. Their intersection of cost to build and certify, lifting power or freight capacity, weather dependence, size, safety, profitable use cases despite low speed, is quite small.

Segway.

[1] https://cdn57.androidauthority.net/wp-content/uploads/2013/0...

Virtual reality in 1987, 1992, 1998?, 2005, 2015 ...

"parallel computing" has been the next big thing several times since Cray; but it never "died out", it just keeps grinding on the fact that human thoughts are pretty serial, and our computers mostly encode and track with our thinking.

This is where pulling up a stack of old Wired / Omni / Popular Science and similar magazines, as well as Gartner hype-cycle predictions and forecasts would be handy.

"Hot technologies of " should be a good keyword for search.

aspect oriented programming

https://en.wikipedia.org/wiki/Aspect_oriented_programming

Second Life and all the similar stuff.

Iirc IBM even held an event there and had like an official place.

Cool concept tho.

It was known 15 years ago that sensors will be the next big thing, but Kinect did not make it. It was later repurposed as an AI sensor.

Sensors are more important than ever, but they became technological details as opposed to selling points.

VRML

https://en.m.wikipedia.org/wiki/VRML

Most tech trends are less revolutionary than they first appear. Really life-changing stuff doesn’t come along that often.

Art NFTs are trendy but the space is not going away. NFTs are what BTC use to be ten years ago.

Semantic Web.