[n4r9]

Banks' Culture series is certainly in this vein. In a post-scarcity society not only is there no limits on energy, but there is very little additional benefit to gain from violence to others.

A potential counter to your post would be LeGuin's "The Dispossessed", where a resource-strapped planet-mining society maintains an anarcho-syndicalist society without private ownership, centralised government, or military forces. The likelihood of defection is minimised by firstly the values passed onto younger generations in their education system, and secondly the lack of actual benefit (since few people would follow you and there's not much material wealth or power to gain). Perhaps this is the "other extreme" in which anarchist principles can be explored.

[api]

Yes, humanity has used mechanisms like LeGuin’s before. It’s called strict theocracy.

A lot of the anarcho types I’ve met have a blind spot there just like they do with energy. They tend to be social liberals, LGBTQ, etc. and they don’t think about the fact that such societies in real life (not in fiction where the writer is god) tend to be extremely conservative and rigidly traditional. In practice there’s often brutal enforcement too.

The conservatism emerges naturally from the need to strictly maintain the society’s value system to maintain a fragile high cooperation state. Any deviation creates social fragmentation which opens cracks.

I think this is probably why historical civilizations evolved to be so conservative and why social liberalism combined with high trust is a feature of the higher energy industrial cosmopolitan state.

So if you don’t want to live in a strict theocratic state but still want equality, figure out fusion or cheap batteries.

You either overpower entropy with overproduction (cheap energy and cheap stuff) or by finding a cooperative state and then exterminating all deviation from that state with repression and violence.

[n4r9]

What about Rojava? Maybe not strict anarchism but not too far off. Definitely not a theocracy or rigidly traditional.

Paris commune, revolutionary Catalonia and Ukrainian free state also spring to mind, though all were bowled over by neighbouring forces.

[api]

Catalonia is one I'm familiar with as an example of something a bit like syndicalism working, but it isn't that big and it isn't entirely standing on its own.

These also, as you say, tended to get bowled over eventually.

Try to scale these systems to the whole world and I don't think it would work... not unless you're much closer to post-scarcity.

[n4r9]

One thing worth noting is that Anarres in The Dispossessed has a population of only around 20 million. It's not actually that much bigger than revolutionary Catalonia was - maybe 2-3 times the population?