"Economy" by merits of its definition is an applicable term for hunter-gathering societies. And is used widely in this quality, in fact.

Nobody says they couldn't find a time to do carving (existence of the artifact shows they could). The issue in question is comparative value of the time spent on it. Hunting, gathering and concomitant works were certainly both physically and mentally very demanding activities, and their way of life required thoughtful spending of energy. Consequently, whatever irregular pastime they had should have to be extremely valuable. It makes 'toy theory' somewhat unconvincing.

Pastimes are in fact incredibly valuable. And it's possible the motivations that led to the creation of this artifact wasn't just all about the end product.