The author doesn't touch on it much, but part of the added complexity is each person thinks differently too.

“Create a window with a table view, and then when someone clicks a button, add an entry to the table view”

If you asked a room of 30 people to draw you a picture of exactly what that sentence means, you will get 30 different results. Building on your comment, I'm not sure the actual act of programming would be hard if you had to take only 1 person's viewpoint into account and work off that.