Either no one paints themselves to appreciate your idea or no one who paints uses a spray technique.

Why buy a machine like that when you could pick up a brush? A machine like this would need constant cleaning and would also give an uneven finish. If painting like this is desired, i once loaded a garden pesticide spray bottle with a very good, fine spray emulsion. It looked awful.

There is far less clogging problem with the proposed system than with a standard spray gun and far more flesibility and tolerance for variations in viscosity of the paint. And the system is much easier to clean than a standard spray system. Do not blame a bad job on equipment when your own inexpertise might be the problem.

Many years ago, my father bought a painting gadget that was somewhat similar to what you are suggesting. It consisted of a container with a motor that attached to the top. The motor spun a horizontal rotor inside the container. The rotor was near the top of the container, just below the motor. A shaft ran down from the center of the rotor to the bottom of the container. The shaft drew paint up(I don't remember exactly how it lifted it, it may have had an impeller) and poured it onto the rotor. As the rotor spun, the paint was thrown off of it by centrifugal force. There was a sliding cover on the front of the container, level with the rotor. You could slide this cover open sideways to set the width of the spray pattern. The paint that hit the inside of the container and cover would just run back down into the bottom of the container with the rest of the paint. It worked surprisingly well and was very quiet, a lot quieter than a Wagner.