* 2017 - the year of 3D TV.
* 2019 - the year of VR
* 2021 - the year of the Metaverse.
All duds, or no more than niche products. Related duds include quantum computing, fusion power, and self-driving cars. (There are self-driving cars that work, from Waymo and Cruise, but they're a long way from being cost-effective.)
On the other hand, there's lots of work to be done deploying the stuff that works. Solar. Wind. Batteries. Electric cars. Desalination plants. Automated manufacturing. Electrical transmission infrastructure to get power to where it's needed. All are profitable. None has either huge margins or monopolization potential. This discourages the Silicon Valley funding model.