I agree with you entirely right up until you say you can separate aesthetics and functionality. While you can do so arbitrarily, they're both so interdependent

I agree with you entirely right up until you say you can separate aesthetics and functionality. While you can do so arbitrarily, they're both so interdependent that neither can truly excel without a certain amount of care taken for the other. Good functionality improves the aesthetic experience of a UI, and good aesthetics improve the conveyance of functionality. You'll find varying emphases between these two all over, but very few successful products make it with a significant disconnect between them.