With more time to think about this, and after rereading your comment I'm providing a new answer. Every example you listed I would consider building. You only l

With more time to think about this, and after rereading your comment I'm providing a new answer. Every example you listed I would consider building. You only listed examples that relate to creating software. I'm sure the PG essay didn't mean to restrict all possibilities of what people could do to just creating software. On one end the distinction is clear to me. A security guard maintains the security of a facility. A nurse maintains the health and well being of patients. A janitor maintains the cleanliness of a facility. Once you start bringing repairs into the scope of maintenance I can understand the distinction being blurry. I'd draw the line where a repair restores functionality to a previous state without any material improvments (to functionality or longevity). If there is a material improvments to the previously optimal state it's augmentation and therefore building.