I agree that working more does not necessarily result in being more productive, but is there anything more specific you can add? Sometimes working more does mean being more productive. Sometimes it results in less output per hour, and depending on that haircut, can net at more or less productivity. Sometimes the working more is a prerequisite to learning something that you can leverage later on.

What was your point in mentioning that to OP? It seems like a bit of an aphorism that doesn't add much to the conversation except to dull GP's point.