When exactly did we start to think that the point of humans was to be productive, instead of thinking that the point of productivity was to take care of humans?
@dougwade @ainmosni I would think that he was influenced by the Reformation. Most factions – but especially Calvinists – started emphasizing labour as a way to prove one's worth in the eyes of God (See e.g. Weber: The Protestant Ethic and the Spirit of Capitalism).
So to answer your rhetorical question: roughly 16th century.