Wireless electricity. Specifically, Nikola Tesla’s Wardenclyffe Tower. Took a fortune to build, but never panned out. Wireless electricity could still make a massive impact. It works, but it doesn’t scale. In fact, the U.S. military is still trying to transmit energy wirelessly.
Various screwdriver standards that were more theoretically efficient than widely-adopted standards (ex: Philips, Turner). But weren’t deployed well commercially.
Keyboard layouts like Colemak / DVORAK that could be more efficient than QWERTY but didn’t gain wide adoption.
For historical examples, consider:
Wireless electricity. Specifically, Nikola Tesla’s Wardenclyffe Tower. Took a fortune to build, but never panned out. Wireless electricity could still make a massive impact. It works, but it doesn’t scale. In fact, the U.S. military is still trying to transmit energy wirelessly.
Thorium nuclear reactors. Nuclear fusion reactors. Any number of alternative nuclear reactors that could theoretically reduce waste, increase safety, increase efficiency, and beyond.
Various screwdriver standards that were more theoretically efficient than widely-adopted standards (ex: Philips, Turner). But weren’t deployed well commercially.
Keyboard layouts like Colemak / DVORAK that could be more efficient than QWERTY but didn’t gain wide adoption.
Here’s an entire HUB of failed government projects. As one example, how the UK government failed at railway privatization because policies didn’t handle recessions well, despite the government’s major support.
One general theme = for any standard X that we use, there was probably a better standard Y that wasn’t widely-used enough.
Another general theme = when it comes to failed stuff, government archives are a great resource :D