You might find
Cool Gadgets that Went (Almost) Nowhere
and
Experiments that failed in the late 60s.
—of some interest.
Family lore has it that in 1917, during the Great War, my great-grandfather invented some kind of death ray, but it failed. Aparently it was a few years ahead of it’s time. 
Jack
Somebody in the Middle East invented batteries sometime around 200 BC - 200 AD (link). No one knows what they were used for, but certainly people of that era didn’t have any real understanding of electricity.
Heck, you could put TV itself in the “before its time” category. For about 5 years either side of 1930 there was an abortive boom in mechanical scanning television, with experimenters building stations and sending simple programs. Hobbyists could tune these in on a shortwave radio and hook up equipment costing only a few dollars to see the small, crude pictures. One or two even recorded them on a turntable, creating the first videodiscs. Cite (one of many).
Of course, once electronic TV became feasible, this abortive technology officially “never happened.”
Binary Code existed way before computers.
The best guess I’ve heard is electroplating.
I had a friend in the very late 80’s, or early 90’s who talked about the internet and how so many services needed to be paid for, plus the new shopping sites (e-bay) that had appeared. It was such a hassle to always enter his CC number and hope that the info was secure. He speculated about opening an on-line banking system that people could use to pay for all their things and have it charged to one account.
He never took it any futher than talking about it because he thought nobody would go for it. Then a couple years later I showed him an ad for Pay Pal and he nearly bruised his forehead from all the :smack: :smack: :smack:
I would just like suggest that “inventon” be declared the smallest unit of inventive thought. However, it is so small that perhaps kilo-inventons (KIvs) be used in everyday writing.
This post required a femto-inventon of creativity.
I do. Thank you, all of you.
What about the Antikythera computer, dated 56 BC?
I thought of pre-measured peanut butter sticks (and posted about them on this very message board) back in 2000, and they were first marketed in late 2004.
I had to write a children’s story for a 9th grade English assignment (in … 1993? 94?). It was about a kid who had a toy that he loved more than anything - until the super-cool new robot toy came out and he ditched the old one. Story was from the toy’s POV.
Shortly after that, “Toy Story” previews started coming out.
Granted, I’m sure the story I came up with wasn’t as “inventive” as I thought it was, but it did tick me off that Disney “stole” the plot and made a billion dollar movie out of it!
That reminded me of Hero’s steam engine, built in the 1st century. It was basically a teakettle rigged to supply steam to a hollow ball with tubes sticking out, making it spin. Large scale steam engines would not come until the late 17th century.
When I had two parakeets back in '96 or thereabouts, I’d sometimes let them fly around the house. Problem was, birds need to defecate every 15 minutes or so, so you can imagine results. I made a crude “bird diaper” using tape and folded paper towels. (Mind you, I was in 3rd grade at the time.) Then, a few months ago, I heard about this website. A great deal of auto-kicking was done, though the product on the website seems much more well designed 
It was the summer of 1985. I was home from my first year away at college, sitting at a bar with one of my friends who stayed back home. We were talking about bars in general, and the conversation turned to our dream watering holes; the kind of place we would open if we had the money.
“You know what would be cool?”, my friend said. “What if you had, like, 20 televisions or so, all of them shoing different games from different sports? The floor could look like a basketball court, and you’d have autographed jerseys and gear on the walls – you know, hockey sticks, baseballk bats and stuff like that? Wouldn’t that be cool?”
I only realized about seven or eight years later, when I actually stumbled upon such a place, that my friend invented the sports bar.
There were plenty of sports bars before 1985.
Back in 1996 or so, my friends were planning a move halfway across the country. I watched in amusement as they filled box after box with their stuff. Boxes of every size and shape filled their garage waiting for the moving company to arrive. I thought about what a pain in the ass it was to have to load those zillion boxes onto a truck and then unload them at their destination. After looking at the containers used to ship things all over the world, I thought about a version for regular people.
It looks a lot like this.
By the early 80’s you would have been too late by 15 years. The office fax machine was introduced into the market in the late 60s by Magnavox and then Xerox (who bought the product line from Magnavox). Competition was provided by another company, “Graphic Sciences”. Acceptance was slow because of the limited bandwidth available through an acoustic coupler and the cost of bandwidth compression electronics.
You can see one of the earliest generally available machines in the 1968 movie “Bullitt”.
Sir John Harington invented the flush toilet back in the 1590s, but it didn’t really catch on – presumably because if you actually had enough money to have water piped into your house, you had more than enough money to have servants empty your chamber pots, so you probably didn’t see the point.
In 1970 or 1971 I talked with a guy in line at the Unemployment office in Santa Monica. He told me he was working on making a device with no moving parts to record and play music.