What he describes (a product growing in complexity) isn't a typical economics of scale type of product. I'd also argue that the general observation is true for all complex products. Even a car has relatively high R&D cost and only reaps the benefits of economies of scale (lower per unit production cost than the competition) once it is ready to ship. Unit 1 is going to be very resource intensive, the following units are what contributes to the scale (and like he said for software that scale is amazing).

However maintenance cost in software are usually really high especially since there is a tendency to gradually "improve" the same code base instead of ripping it out and building a new one every n years (buy a new car).