If it absorbs blue light, we see red. Since none of the visible spectrum is absorbed by the altered pigment, all of the visible light is reflected, and we see no color. Seldom is this process complete, and red usually becomes pink. Inorganic pigments are not affected by the free radicals. Yup, get out your checkbook.
Automotive paints contain UV absorbers and free radical quenchers.
O'Donnell says even though the technology is there to make paint and colors last 100 years, it would not be a wise investment for homeowners. Most folks tire of a color in 20 years or less, and decide to repaint. If the paint is over-engineered, the consumer will no longer be getting good value for the money. Pigment used in high concentrations is more stable. The irony is organic pigments have a very poor hiding ability.