I have seen the technology come and go. Some of it was good, but it didn't stick. I have seen 3D cameras come and go (in the 80s) and sort of come back. Mini CD and DAT recorders and players. Car phones that had to be installed, and actually looked like an old home phone. But now we have cells so we don't need them.
The Kodak Disc camera - not a bad idea, but tiny film made lousy pictures - most cell phone have a better camera now.
What are some good ideas that didn't stick or find a market?