Unfortunately, I don't know about any study correlating bullying (or lack of it) with future success or failure in life. For example, do we know that being bullied in childhood encourage or discourage (or have no correlation with) development of one's psychological resilience?

While playing - growling, biting, jumping - wolf puppies prepare themselves to live as wolves. Humans are the most cruel animals on Earth, thus it seems natural that the play of human puppies is much more cruel than that of wolf puppies.