Some say it's because we haven't tried hard enough. We say this approach has failed. We need to take a fresh approach Make some new assumptions. See if they work better. Our assumption is that there are no social laws.
Every group develops independently.
Each group develops its rules and mores. So the only way to learn how to facilitate groups is to go out and do it. Then come together to reflect on what's working and what's not. Then go out and do it some more. The similarities in spoken and unspoken languages between groups from similar backgrounds will enable facilitators working with such groups to be able to learn from each other's experiences.