Google glass failed, but I suspect that they allowed it to fail due to lack of persistent development.
The way most people work is that they try something, it doesn't work, and they give up. I've heard lots of things like "I can't learn to whistle, I've tried" and "I tried that, but it didn't work". Mostly it's amateurs building stuff and giving up on the first try: "I put the circuit together and it didn't work", or "I tried to build a spice rack for Marge, but it turned out awful".
If you really want to make something, you have to be prepared to throw the first one out and start over. If the circuit doesn't work, find out *why* it didn't work and fix it. If your spice rack is awful, spend some time on YouTube looking at proper technique, then spend some time using the router (or table saw, or whatnot) with pieces of scrap until you get the hang of it. Then start the project over.
Google glass could have been popular if they noted the feedback and piloted the project into more popular waters. For example:
1) A flip-down cover for the camera, so you can interact with people and they know you aren't recording them
2) A less restrictive interface, so that developers can show anything instead of storyboard images like a viewmaster. IOW, a direct graphical interface.
3) a less expensive device (costs $150 to make, $1500 to buy). (Note: Cell phones have largely the same functionality and don't cost $1500)
Rather than fix the problems, they decided to just let it die. Maybe they did market analysis and thought that it would never sell in any form, but I really doubt they went that far.