Because evolution isn't a nerd optimizing a design. Design implies intent. Evolution is more random and serendipitous than a nerd with any sort of intent. It's

Because evolution isn't a nerd optimizing a design. Design implies intent. Evolution is more random and serendipitous than a nerd with any sort of intent. It's not engineering. There's no specs & recs or post mortems or blueprints. Evolution is too beautiful, random, and mysterious for the enginerd to appreciate and understand.