The eye can see lots more than 262,144 colors. What's the number, 10 mil? Quick googling gave varying results, depending on what's counted as a distinct color (e.g. differences in luminance).
Yes but a 6 bit display accomplishes millions of colors through dithering, and your answer says nothing about whether that kind of dithering could fool the eye.
Since all colors on a LCD screen are dithered between red, green, and blue anyway, and the human eye has no trouble handling that, the question is whether a higher level dithering would be similarly undetectable.
I'm no color expert but even I could tell the terrible banding issues with gradients on a MacBook's screen. It's extremely apparent as soon as you throw a smooth gradient on screen.
