I would argue that Rojava is one modern case that still shows hope. Although not as decentralized as those other examples, perhaps this is also why they're still there 11 years later.

I agree. Though unfortunately there have been reports of them slowly centralizing power away from community councils toward the military over time. Even still, it's offering far more freedom and diversity than any of the surrounding countries. I'm rooting for them to succeed.

Ehh, I would put it differently: purposefully decentralized societies are ineffective, and create a power vacuum that tends to be quickly filled. Assuming they would have worked requires a view of human nature that I just don't buy. Along comes a Lenin, or a Mao, or a Trump, or a Robespierre, who starts giving rousing speeches about how dangerous forces are rising against the movement, and next thing you know you've got concentration camps, guillotines, mass shootings, and so on. And that environment rewards authority and tyranny.