As a car enthusiast, I can think of a good one, the Ford Nucleon.
During the 1950s and 1960s, there was considerable interest in nuclear power and its potential applications. This led to the idea of using nuclear energy to propel cars. The concept behind a nuclear car was to utilize a small nuclear reactor to generate steam, which would then power the vehicle's engine.
Of course back in those days, this was extremely futurustic and some at the time thought this would be a game changer, but ultimately, the safety aspect was one of the biggest reasons why this idea was dropped, and I probably don't have to explain why it may not have considered to be safe, I mean, it was using nuclear power, so even if the engineers tried to make it as safe as possible, IF something went wrong, it would have been catastrophic.
Ever since then, the interests in the automotive sector has shifted to Electric and Hydrogen.
Still, a very intriguing concept car and idea.
Outside cars, you have blimps, and I personally believe if we tried to make something like a hindenburg today with existing technology, we might have been a lot more successful than back then (as it goes way back to 1930s), there are still some blimps used occasionally, I also don't believe those use hydrogen(?), but they are not the "game changer in air travel" it was once seen as, although we can't rule out a comeback.
What about you guys?
I mean, depending on your definition of 'supposed to be,' one could argue that the Juicero was, amidst a sea of devices and peripherals obsessed with getting a piece of the action on the Internet of Things, poised to revolutionize the way the home consumer juiced their fruit and veg. It's not even all that difficult to imagine the pitch those responsible might have led with: "No more squeezing, no more cleanup, just fresh-pressed juice delivered to you weekly at the push of a button."
For those readers who don't recall the Juicero, here's what was wrong with it:
For starters, it was way too expensive. If I told you all this thing did was take a bag of fruit chunks and squeeze it out of a spigot, how much would you think such a device would set you back. $40? $60? $100? Try $699. They did later lower the price... To $399.
But surely this marvel of engineering would justify the ludicrous price tag, I hear some of you say. Yes, this wondrous device was capable of a great many things, including... Pressing two plates slowly together to crush chunks of fruit and squeeze them out of a bag. And... Well, that's really the whole deal. But certainly not, say, something you could easily do by hand, and save yourself half a grand.
Actually, I lied about the above part - it was capable of a few other neat things, when connected to the Internet. Well, it required an internet connection to work, so, hope you have that in your kitchen! But it offered so much more than squeezing juice bags slightly better than human hands. It could tell you if the juice bag was expired! Or there was a safety recall! Or a non-juicero brand! And refuse to squeeze the bag in any of those cases.
Obviously, the thing flopped, hard, in one of those rare cases where consumers by and large realized "Hey, this thing is really fucking dumb!" But it called out to a much larger issue, where Silicon Valley entrepreneurs were fetishizing the possibility of the Internet of Things, with similarly ridiculous products shoehorned with 'smart' capabilities. Smart shoes, smart salt shakers, smart umbrellas, the whole fucking nine. Everyone obsessed with collecting data and offering minimal benefit to users in exchange. And the worst part of is, they didn't really make money on the Juicero itself, so over-engineered it was. The long term goal was to charge for subscriptions of overpriced juice bags, at $5 a glass. It was a preview of things to come, I suppose.
I remember they tried to use the environmental angle for marketing. They claimed that they were making use of discarded fruit pulp that would have gone to waste.
But of course it was actually an efficiency nightmare. They shipped the pulp to their factory, then shipped the weight of the pulp plus juice to the customer, who would then throw out half the weight of each package.
It would have been way more efficient for them to just buy the pulp, squeeze it in industrial quantities and sell bags of juice like some trendy health thing. But of course then they would have been a juice company instead of a tech company, and juice companies don't get as much venture capital.