Why don’t these exist?

Spherical computer monitors
I first thought of spherical computer monitors around 2000, looking at the globe we had bought years earlier to teach the children geography. Of course, I thought at the time with its technology a spherical screen was impossible.
Then they came out with the stupid curved television screens a few years later. The super globe was possible! A spherical screen with a computer inside that could have a map of the world, with features marked in any language you choose, with changing names like Bombay to Mumbai and Burma to Myanmar with a few clicks or keystrokes on a tablet or computer. Your globe would never be out of date!
It could be used in history classes, showing changing country borders over time, corresponding to information shown on a coupled flat screen. It could be changed to a topographical map, a weather map, a satellite map, a temperature map, or any other kind of map. It could look like a basketball or a giant baseball. It could look like Mars or Jupiter, mapping the surface of any planet. It could do a thousand things I haven’t thought of.
When they built the giant one in Las Vegas I wondered, why aren’t smaller ones in homes and classrooms?
 
Strobe tail lights
You’re driving along and see the car ahead brake, so you let off the gas. But he’s going into a skid and his ABS is taking over, quite a bit different than just slowing down. At highway speeds you can go an awful long way in two seconds.
The ABS should be tied to the brake lights, so when you make a panic stop, they strobe and the driver behind you doesn’t have to make a panic stop. This would prevent many chain reaction wrecks.
This should be mandatory on all new vehicles!
 
Footstool Fans
They used to make these. You can still buy used ones at the ridiculously high price one usually pays for antiques, but they’re fairly rare. They went away about the time central air conditioning became common.
It was a fan about a foot or two in diameter inside a slightly larger tube, illustrated here. The air came out of the top when you turned it on. Almost all homes had one.
But then central air conditioning became common, and people gave up fans entirely. In the eighties, ceiling fans came back in vogue and are still being installed and used. Why not the footstool fan? They could save money on air conditioning!
Back when they stopped being common, fans were expensive to run. There were no rare earth super magnets, just inefficient steel that required a lot more electricity than modern fans. And there was that cord to trip on, and likely lawyers loved those cords.
But today we have lithium ion batteries that power everything from telephones to automobiles, and super magnets that make the super motors strong enough to make almost any EV easily beat almost any piston vehicle in the quarter mile.
And the motors’ wiring would be simpler for multiple speeds; AC motor speed is governed by the frequency, DC speed by voltage. A motor, variable resistor, a switch, and a rechargeable battery would be all it needed.
They should bring them back!
 
$25,000.00 EVs
This one I can actually answer, and the limitation has nothing to do with technology. The limitation is the greed of the manufacturers.
A piston drive train is a complex device with thousands of interlocking moving parts to wear and break; a Rube Goldberg device invented almost two hundred years ago and made more complex (some might say overly complicated) with time. Complexity has the disadvantage to the device’s owner of maintenance and expense.
However, it has definite advantages to the manufacturer, whose wares have thousands of moving parts. He makes more income maintaining and repairing what he has sold than he earned in the initial sale, sometimes through several owners. A dealer-to-junkyard maintenance gravy train.
The EV power train is a simple device with fewer than two dozen moving parts and needs absolutely no maintenance! The only reason automakers build EVs at all is the fleet emissions requirements from governments, so they have replaced their biggest V-8 drive trains with motors and batteries. None of these muscle cars and luxury sedans have ever been cheap!
 
Variable speed limits
This was impossible a couple of decades ago, but would be dirt-simple today.
Different driving conditions require different speeds. I’m not going to drive anywhere near the speed limit if there’s snow on the road, or a bad summer storm. But I’m not your average driver, I was re-trained by the USAF to be a professional. There are drivers out there with very limited intelligence who can’t understand the concept of “too fast for conditions” (which can garner one a traffic ticket or a totaled car) who drive the speed limit on ice, endangering not only themselves but everyone else on the road.
Many people think four wheel drive gives better traction when driving, when it only doubles the number of powered wheels when taking off from a start. It’s great for keeping you from being stuck in the snow, but will stop no faster than a two wheel drive car and will slide just as easily.
When the normal limit is seventy and it’s a beautiful, dry sunny day and you are the only car on the superhighway the limit could raise to eighty. When there’s moderate traffic it could lower to the normal seventy.
When there’s a heavy fog it could lower to 40 with a minimum of 30, or lower, depending on the density of the fog. A couple of years ago there was an Illinois farmer plowing a dry field in a strong wind (and wasting his topsoil, the moron) with a visibly impenetrable dust cloud covering I-55, and idiots would rather drive blind than pull over, so there was a horrible multi-vehicle pileup killing dozens and injuring more.
Had there been variable limit signs, stupid lives could have been saved.
Taxpayer money could be saved during road construction, as well. Presently on the interstates when there’s construction the speed limit signs are covered and temporary 55 mph signs placed. This takes manpower, the most expensive part of any endeavor. With electronic variable speed limit signs, a switch could be flipped, or a couple of keystrokes on a computer at the state police headquarters, and the signs in the construction area could change.
 
Easy to program key fob garage door openers
My car has a built-in garage door opener on the rear view mirror that’s incredibly easy to program, using the remote that came with the garage. You hold a button on the mirror and a light flashes. Then hold the remote button and the light stays steady, and goes out when you release the buttons, and the car’s opener works. Easy.
My garage remote is ancient, clunky, and its battery cover is a piece of tape, and I wanted one that was a key fob, so I bought one from Amazon.
Now, I started programming computers in 1982 in many languages, including assembly. I’ve built and repaired computers. But I couldn’t program the key fobs. I’m 73 and refuse to climb a ladder.
So I called around, and nobody had easy to program remotes, let alone ones that were key fobs. So I gave up.
Then the ancient remote broke. At least I could get in the garage with the car’s button, but I still needed a new remote, so I called a garage door company who sent a technician (a man in his seventies eager to climb a ladder is a fool) with my new key fob remote. Then he climbed the ladder and programmed it. The door came down a couple of feet while the garage light started flashing before opening again. The guy whose job was to do this had a hard time doing it, but finally got it programmed.
But I see no technological reason whatever why I can’t buy a key fob remote from a hardware store that is easily programmed without climbing a ladder, like the garage remote in my car’s mirror!
 
Automatic car windows
My car has automatic windshield wipers. Why can’t the same technology roll the windows up when it’s parked and it starts raining? Car windows haven’t had manual cranks for decades! Because it could only work on an EV because a 12v car battery couldn’t handle it?
So put it on EVs! The problem, of course, is that it would give EVs one more advantage over piston cars, and the automakers hate EVs; as mentioned earlier, there is no dealer-to-junkyard maintenance and spare parts gravy train with EVs.
Except... how much juice does a water sensor require? Or the small 12v motors in the windows? I doubt the 12v car battery would be insufficient unless it was parked for a long time, and if the windows are already closed it could shut itself off with the car. And piston cars have the same computers as electric cars; if rolling up the windows uses too much electricity, have the computer start the car, roll the windows up, and shut it off again.
Worries about little fingers being crushed could be assuaged by always leaving half an inch (a little over a centimeter) unless a human was rolling the window up with its button.
 
Lengths of highway lines matching speed
Last year when they repaved the four lane street in front of my house, I noticed that the lane marker lines were longer than normal. Then this idea hit me: why not have the lengths of the lines that mark lanes twice as long on a 70 mph highway than a 35 mph highway, with all speeds so marked? When you exited the interstate, the shorter marker lines would remind you that the limit was no longer seventy.
 
Automatic audio frequency adjustments for air pressure
I’ve always had very good audio systems, with flat frequency responses past human hearing limits, and multi-driver speakers, at least three way with at least a twelve inch woofer. One system I bought in the Air Force was even better, five drivers per enclosure and including its fifteen inch woofer. But there’s one thing good audio systems lack.
When it’s storming in the spring, the sound is heavy on bass; the air pressure is low during a storm. In a summer “heat dome” the treble is clear but the bass is wimpy. Thin air mutes high frequencies, and high pressure heat domes in the summer mute low frequencies. Your stereo will sound far bassier in Denver than Miami.
Audio systems should have an electronic altimeter (air pressure gauge) that can adjust the frequencies going to the speakers to keep the frequency response flat across the spectrum regardless of weather or altitude.
 
EVs without 12v batteries
Perhaps there are some. If so, I haven’t heard of them. Despite its eight hundred volt main battery there is a second battery, a normal twelve volt lead/acid car battery that is used to run all of the radios, fans, computers, and other twelve volt components.
This is brain dead stupid... or would be except for wanting that dealer to junkyard gravy train on parts and maintenance. The big battery under the floorboard lasts ten years or more, the little one under the hood five at best.
There is more than one method for stepping high voltage down or the big battery couldn’t charge the little battery! I don’t understand why the lead/acid battery is there in the first place.