Large groups need ways to coordinate. That does not automatically imply that every layer of coordination requires permanent sovereignty over the layers beneath it.
The proposition
Keep the foundational layer extremely small. Allow communities to create additional agreements locally. Let those arrangements differ, compete, expire, fork, and be replaced.
Sunset everything
An agreement that made sense for one generation should not automatically become authority over the next. If cooperation still creates value, people can renew it.
What should be tested?
The interesting question is not whether decentralized governance sounds attractive. It is where it breaks: disputes, mobility, common infrastructure, external threats, free riders, and coordination between communities.