> Engineering is about creating something that serves a purpose, while operating within a set of constraints.
A builder fits that description. Even a cook fits that description.
Engineering is something else. It's hard to describe what it is, probably why it has its own word. Dictionaries probably offer a definition.
> A good engineer will acknowledge this tradeoff between robustness and cost and behave accordingly.
An engineer will never intentionally produce something shoddy for cost reasons. They will simply refuse to do it. What you are getting at it some tasks don't require an engineer at all. You want to build a bridge to span a kilometer of water? You need an engineer. You need to occasionally cross a ditch? Anyone could lay plank across. No engineer required. The author makes this point too, with software craftsmen.