Capital punishment and what we call murder today have, in certain contexts, been norms in many past societies and cultures. There’s so much complexity in how these traditions and systems developed that hypotheticals, though intriguing, often produce results that don’t really make sense in the real world. The cultural effect of the sudden introduction of hardline capital punishment here in the US would obviously be incredibly disruptive, riots in the streets and perhaps more. I can’t personally envision a society reliant on elimination that doesn’t eventually look like North Korea. But there’s always the possibility that future research indicates permanent removal or destruction (either via death or transformation to the point that a person is so far-removed from their original self that the destruction of said person has essentially occurred) is the best option in certain cases, if not many. I like restorative justice as a concept and it’s encouraging to see places try out new systems, but I’m not sure there will ever be a time when long-term incarceration won’t be a part of it.