I think the article misses something pretty important though - not every customer is created equal. Design on a micro scale (changing the color of a button) is a force multiplier at scale for sure. But design on a macro scale can have an effect on customer value. This is the whole idea behind luxury brands.

If you have 5x less traction than a competitor but you can monetize yours 10x better, you're in a way better position. Aesthetic design can be a huge driver in higher value users.