It happened before relatively successful with slavery and is partially happening with the death penalty. For me it seems like a very long way to go though.
Slavery and the death penalty are poor analogies, and not just because slavery was stopped through quite a bit of violence, and the death penalty/imprisonment exists as an alternative to vigilante justice only by virtue of the state's monopoly on violence.
"If everyone just ..." is always silly, but it's especially silly when it comes to the belief that order can be enforced through anything other than -- ultimately -- the threat of violence. Everyone will not "just".
Human order is fundamentally kept by there being a true threat of violence enforcing it.
If you forget that reality and abandon your ability to project violence, someone else will remind you.