Magenta, the color that should be the color of the year 3000.
Why doesn't it exist? Simple, it's just too good. It's like asking why pineapple doesn't exist on pizza.
Think about it, if magenta was a color, it would mean that someone, somewhere, somehow managed to create a color that's just a little too much.
It's like the universe said, "No, you, with your bright pink and your red, you can't have both, it's just too much."
But what if we made it exist? What if we made it a thing?
Or maybe it's already real, and we just don't want to admit it