Being rather contrary here, but is there any evidence that bullying actually improves some people's lives? As a victim of childhood bullying, the experience was awful, but I learned a thing or two as well.
My experience was not as bad as some others on this list. I believe that is because girls are psychological bullies, and boys are physical bullies. My husband was chased and beaten up until he the beat up the lead bully.
I met my lead bully as an adult. I was surprised to find out that she did not realize she was a bully. She acted as if we were childhood friends. One of her friends apologized to me, so others certainly realized.
Her life did not go as well as my life. I suspect it was because the traits that made her a bully as a child did not work for her as an adult.
Whether you learn something from it or not, the purpose of school is to learn. If you went into work every day and had someone beating you up every day, would you be productive? Probably not (and btw, the only reason we have systems where this happens at all is because of what adults want, not what kids want).
Please replace the word bullying in your question with the word rape or mutilation or imprisonment or starvation and see how horrible that line of thinking is.