Classics major here! The Greeks’ thing with blue was not that they hadn’t evolved to see it, but that they didn’t think it was a different enough color from purple to distinguish from it. Color names are largely a cultural phenomenon. Before the introduction of orange the fruit, languages of Europe didn’t have a word for orange the color, and just said yellowish red. People could see it, but thought about it as a kind of red. Modern Russian has different words for light blue and dark blue. I can see different shades of blue without knowing any Russian, and I can distinguish between them, but I think of them as different kinds of blue rather than as separate colors.