To add to Tirisias post-labor/post-scarcity society, a few years back, I watched a video about the Venus Project (which I can't find anymore). The goal is to live without a government, without money, and to use science for greater technological advance and distribution of resources instead. I will summarize what it says because it has an answer for violence:

Money stops science from evolving in a sense because for profit, products need to deteriorate so the consumer will buy again. If there was no money, we could produce products which would last for lifetimes. This would resolve the scarcity problem quite fast, and we technology could evolve faster. Everything would be sold in freely and people would take what they need. In a world where everyone can have anything they want, owning material loses all its value. People no longer desire objects as they do now so they consume a lot less. Also, there is no theft because there is no need for it. This world would have a different culture, where students don't go to school to get a job, but by interest.

And I guess, at that point, violence can be dealt as in the animal world. An eye for an eye. If someone attacks you, everyone attacks them back?

Anyways, that was a rushed description of a video I watched a long time ago, and they themselves say that you can't understand the Venus project by just watching a video of it, you'd have to study it well enough. It's complex. But it's inevitable. The world always change. And there will be something after capitalist democracy.