At the end of the day, the two mediums still require the same elusive quality: design. The composition of walls and windows, or the strategy of buttons and images, is up to the designer's taste, experiences, and agenda -- what kind of story the designer is trying to tell.
Compared to construction or web development, this "storytelling" quality cannot be so easily taught. It is the result of endless trial and experimentation -- and the result of a very clearly defined concept and message.
This quality of "storytelling", I believe, is at the heart of all design pursuits, and why we are all in this game -- why we move forward as designers.