I always visualize the walking dead scenario in my head with tribalism and communities.
In some ways yes, some ways no. In TWD, material resources are vital (safe land, food, shelter, bullets etc), but in the future, digital ownership is also important. The arguments are different, when the resources of value are endless.
Will the governance be decentralized but the services are provided centrally?
I think so. And, there will still be centralized governance in some areas, but it will be developed through decentralized means and able to be dissolved quickly if needed. This is the problem now, once in power, always in power - except without a massive amount of bloodshed. If however, the value can be cut off immediately from that power, the "authority" is a servant, it has to do an adequate job, or be replaced.
In TWD scenario, how will the society ensures safety and security? I think, that would be the biggest concern of the population as the centralized state has created that safety(?) net till now.
It would be a fascinating experiment, of course. Let's see if we can witness a solution in between for the transition where two systems collide with each other. El Salvador is gearing up for that centralized and decentralized collision.
How does it ensure it now?
Nothing stops organizing what we have now, it is just reached by consensus, rather than dictation and tweaks can be made at the local levels as required.
Social rules exist but does not interfere with the rewards and punishment mechanism. Yeah, may be the social decision making which is practiced throughout traditional societies.