Anarchism can never even exist, let alone work, because it defines itself in a fundamentally nonsensical way.
It distinguishes itself on the principle of 'non-coerciveness'. But coercion is written into the fact of physical scarcity: if someone wants that food, then someone else cannot have it. Any organisational notion that does not represent that scarcity as constraint on behaviour is useless. It simply fails to address the problem.
What anarchism then does is to confuse and obscure this, or just wish it away. The motif of 'decentralised organisation' is a contradiction in terms: there cannot be structure without some constraint. If every local grouping is always free to decide the rules, then there are no rules. If everyone is free at every transaction to invent their own money, then there is no money. Plus, everyone making up new rules will not scale. (And no, people will not just naturally, magically, happen to agree.) Organisation is essentially hierarchical in its basic one-to-many informational form: there must be some single pattern followed by multiple elements.
What anarchism could sensibly propose instead is more sophisticated democracy: ie, better forms of feedback from participants to rule generation. We cannot avoid rules/structure, but we could more responsively, iteratively, steer the the construction of them.
It's a bit ironic to say anarchism works because people have been interested in it for centuries if not more and yet it has clearly never worked. And then people always bring up something or other "oh, these people were anarchists for 2 and a half months in Spain in 1926, see it works!"
Another glaring inconsistency with anarchism is that if you are unwilling to use coercion or organized force, then how do you defend yourself against another group who will and wants to take you over? You'll just get obliterated and then be forced into their version of non anarchism. And then the nit picking starts "you can defend yourself" yeah but if you haven't been actively cultivating an organized defense force you're going to lose and maintaining an organized defense force involves all sorts of coercion and hierarchies.
No point even writing this stuff, it's not the kind of thing you'll ever convince anyone of who doesn't want to here it but organized anarchism is just such a preposterous idea that it's hard not to.
There are anarchist experiments that lasted much longer, even in the United States. Modern Times in New York was a town that used "labor notes" instead of dollars (within their own community at least), and they had no jails. They existed for 13 years. Eventually some gossipy rumors spread that this eccentric town (which it was) was just a bunch of "free love" weirdos (they were not). The founding members and strongest personalities either moved or passed away, and the remaining people got tired of defending themselves to others, so they reorganized the town as Brentwood. The public library in Brentwood has a neat collection of writings and artifacts from Modern Times, and I once spent a fun day there looking through their collection.
https://en.m.wikipedia.org/wiki/Utopian_Community_of_Modern_...
Home, WA was more explicitly "anarchist." It lasted for about 18 years, and I think from the beginning they had a rough time from neighboring towns as it was founded right about the same time McKinley was assassinated. McKinley's assassin was a self-proclaimed anarchist, so overnight the word "anarchist" became notorious and dangerous in mainstream opinion. There was, again, much outside gossip about the town being a weird "free love" town (which was not such a baseless claim in this case). Internally, it seems people never really agreed on social norms about being nude in public spaces, either.
As to your point of defense, I once heard someone describe that as the major difference between anarchism and Marxism. Marxists generally believe that the State needs to be seized from capitalists, and then we must use the power of the State to oppress the oppressors. That is supposed to be a transitory period, and eventually the State will have squashed all capitalist opposition, at which point the State "withers away." The anarchists see all that and say we should try to jump straight to the good part :)
https://en.m.wikipedia.org/wiki/Withering_away_of_the_state
Funny, I'd rather have you in solitary confinement for the rest of your life then running around robbing people with weapons but hey, psychopath is in the eyes of the beholder.
Just be aware, you can come seize my capital but you better have more guns then I have.
Many anarchists recognise scarcity and admit it's a difficult thing to deal with fairly. But instead of assume they have the one solution and enforce it on everyone else, they leave it to more local levels to agree on a reasonable way to ration scarce things.
You could also easy make the opposite criticism of capitalism: it doesn't recognise abundance and builds almost everything on (often artificial) scarcity.
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Free banking ("everyone making up their own money") was never the disaster currency monopolist would like you to think it was.
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You say locally made up rules that apply only locally don't scale. Does it really scale to have locally made up rules (because they always are) that are enforced globally?
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But yes, many anarchists do exactly what you propose: they experiment way different ways to collectively make decisions. They don't shun all rules.
It distinguishes itself on the principle of 'non-coerciveness'. But coercion is written into the fact of physical scarcity: if someone wants that food, then someone else cannot have it. Any organisational notion that does not represent that scarcity as constraint on behaviour is useless. It simply fails to address the problem.
What anarchism then does is to confuse and obscure this, or just wish it away. The motif of 'decentralised organisation' is a contradiction in terms: there cannot be structure without some constraint. If every local grouping is always free to decide the rules, then there are no rules. If everyone is free at every transaction to invent their own money, then there is no money. Plus, everyone making up new rules will not scale. (And no, people will not just naturally, magically, happen to agree.) Organisation is essentially hierarchical in its basic one-to-many informational form: there must be some single pattern followed by multiple elements.
What anarchism could sensibly propose instead is more sophisticated democracy: ie, better forms of feedback from participants to rule generation. We cannot avoid rules/structure, but we could more responsively, iteratively, steer the the construction of them.