I don't think he's referring to the visual aesthetic. I went through what the parent comment describes and kept re-reading these lines to guess what pg meant: "The Cadillac was carefully designed to appeal to the average driver. The 911 was designed for performance. Which one is better design?". I concluded that he did not mean visual design but instead meant some notion of "overall design" that included both visual appeal and performance, and did not state how he defined the term.

And then I read "It's so obviously superior to the Cadillac that a child could tell it's better" and decided that either he's bullshitting or my design sense is non-existent.