This is my question. If there would be no state monopoly on violence (=regulation), what would stop me from killing my competitor instead of improving my product? A bullet is surely cheaper than investing in actual innovation is.
Well there never has been a stateless (post-state) society so there are only theoretical answers.
Uhm. No. There, you're wrong. Somalia is post-state, and if it's a bad place to live, that's mostly because of how awful the State was before it collapsed. They have a functioning polycentric law system, which pre-existed the state, and picked up right where the state left off when it collapsed, and life has greatly improved since the collapse of the State.
https://en.wikipedia.org/wiki/Xeer