Its a design concept, like a flying concept car at a motor show. These are often design student projects. The thing they’d turn in at the end of the course to get a grade.
They don‘t actually work and many of them only exist inside a computer not physically.
They're not intended to become real products.
Sometimes though these images get spread around the internet so much (like the Elbow cassette player) that people think they’re real. Then the designer sees the interest and has a go at making one (like the elbow cassette player) and finds that reality puts the stops on their fanciful plans. It’s one thing to draw something cool on a computer, but another thing entirely manufacturing it.