I'm not sure I fully agree with the article's takeaway that dogs are only in it for the food. It's a bit of a crude summary. In addition to food, humans provide shelter, protection, love, attention, play time, and companionship - I don't think food is the only driver of the relationship.
My dog will hide behind me if he's scared, and enjoys attention from people he doesn't know - irrespective of whether they provide food for him or not. And he'll cry and ignore food from others for hours if I'm separated from him. Maybe this is just anecdotal data, but seems doubtful.