At least for the 3D printing case you may have just been too early, or the wrong market.
I work at a hardware company and these days 3D printing is invaluable for prototyping and other similar work.
Maybe in a couple of years the same will be true for the others.
I tried 3D printing. The results were subpar and the utility wasn’t much beyond a toy or a hammer.
I tried VR/AR. VR just made me nauseous. AR was a cool tech demo that I would never use because I’m actually trying to reduce my screen time, not increase it.
Tried web3.0. Got scammed.
Currently trying AI. This somehow feels like the real deal. I’m at least using it every day, even maxing out my GPT-4 limits.