What are some solutions that are looking for a problem?

This is more of a humor (obviously), but

* Blockchain - this is usually the first that comes to mind.

* Rust - "hmm, where would I use it now?" is the question you'll ask if you just learned Rust but knew C++ already.

* Vulkan / Direct3d12 - yes, you now have the ability to recreate your own driver from scratch, but who has time for that? Even Microsoft Flight Simulator uses Direct3d 11. GPU ray-tracing will force you to use one of those though anyway.

* WebAssembly - at least in it's current state.

Giving electric cars extremely long range. It would be much more sensible to make substantially cheaper electric cars that have ~75 mi of range, and combine that with a program that gives free rental credits for any hybrid/PZEV car to owners of that car.

Then you can have a cheap eletric car but get access to fuel-based cars when you go on a trip.

8k resolution, Go, Rust, c++, exotic cars, abstract classes, and MattressFirm are all things that come to mind.

I think blockchain is the poster child for this category.

Citizen “militias.”

NoSQL databases.

Consumer VR. iPad pros with M1 chips (ridiculous processing power, not many scenarios demand it). Alexa (besides timers and starting music).

Bitcoin. In my opinion.