In contrast, I've known people who are unwilling go fight. If they encounter a bully, they will not stand up for themselves and either submit to the abuse or run.
In my experience, neither "solution" ends the torment. On the contrary, it just gets worse and worse. Soon they are not just being subjected to verbal abuse. They're getting slapped around like a bitch. Some still won't fight. And then it gets worse yet.
Unfortunately, for those kind the trouble NEVER ends, unless and until someone steps in and fights for them.
I'm convinced that many of those who are unwilling to fight lack self-confidence. The solution for such an individual is to conduct a self-evaluation (or have a competent clinical psychologist conduct a professional evaluation) in order to discern the reason why he lacks self-confidence. When the individual in question knows why, he will also know what he needs to do to gain self-confidence. Just as sharks are attracted to blood in the water, bullies are often attracted to lack of self-confidence; and I'm not blaming the victim by saying this.
All that said, I certainly agree with you that usually the quickest way to stop bullying is to punch the bully in the face. Frankly, he deserves it. (Of course, I'm referring to kids. I assume adult bullies are likely to sue.)