I used to go out with someone who lived in a commune, which operated how you describe here - everybody gets a say in every decision. It was very equitable, but nothing *ever * got done. Part of the roof was falling down and the exposure to the elements was damaging the building at that point. The longer it was exposed the more damage was being done. The wall was starting to crumble. If it fell down it could damage as-yet undamaged parts of the building. A couple of families had already had to move to a different part of the building

At that point it had been 10 years and no decisions had been made. No decisions were close to being made. Their home was literally being destroyed and potentially endangering people -they were and had been no issues more pressing - and nothing has been done for a decade

That was ~15 families living together. And you think it’s feasible to scale that up to millions of people by increasing the group size and number of steps?

Of course, neighborhoods do not exist in a vacuum - neighborhoods would want to work together to share resources and to collaborate to achieve greater goals, so confederations of neighborhoods could be formed. Each neighborhood could select one or more delegates to attend confederation meetings and speak on the behalf of the neighborhood, but not make decisions on behalf of them. Instead, each delegate would attend the confederation meeting, and meet with their neighborhood to bring them news of what was discussed at the delegation meeting. Then, in the neighborhood meetings, each neighborhood would come to their own decisions around what should happen at the confederation level, and a delegate - not necessarily the same person as before - would take those decisions, questions, concerns and discussion points back to the confederation, where either a consensus would be reached, or further discussion - which could again, be brought back to the neighborhood to share. In fact, rotating the role of delegate would be a really good idea, so that multiple people can get a better idea of the issues in the wider community and understanding of how the bottom-up power structure functions.

This sounds like a really good idea, but let me point something out: For the sake of efficiency, it would quickly make sense for most neighbourhoods to give their delegate a mandate of the type "We want something like this, but you can make minor changes to points X, Y, and Z in order to reach an agreement with the others". For example: We want the new road to be a gravel road that's about 2 m wide, but you can decide the exact quality of gravel, and whether the road is 1.5 m or 2.5 m in the meeting with the others. Whether we have light posts every 40 or 80 meters isn't so important, as long as the road is well lit (just make sure the lights are strong enough if they're widely spaced).

Further, once we get to scaling this up from the neighbourhood level to a scale of hundreds of thousands or millions of people, we're going to get progressively more details and specialist tasks that need ironing out: Should there be import tariffs on any goods? If so, which? What should the tax be? Should it be progressive? If so, how should it scale? What should be the standard bridge-height on a highway (very useful to standardise if you want any kind of long-haul transport)? How many students should there be per teacher in classrooms at different grade levels, and what kind of education should we require from those teachers? etc. etc. etc. This absolutely massive number of questions that need answering, will in practice demand that your delegate receives some kind of mandate to make decisions within the limits of what you've decided.

The larger the society in question, the wider those limits will need to be in order for the society to be able to reach any kind of consensus within a reasonable time frame. If every detail needs to go neighbourhood meeting (O(100 people) => neighbourhood confederation (O(10 000) people) => community meeting (O(100 000) people) => national meeting (O(1 000 000) people) and back for every iteration, the kids are going to be grown before you've decided whether a 5th grade teacher needs minimum high-school level or university level mathematics in order to teach science classes, or even before you've decided on whether this should be something you coordinate at the national level or not for that matter.

Once you start giving your delegates a mandate to make decisions within some pre-determined limits.... you've reinvented representative democracy.