> unnecessary concepts of private ownership and hierarchy of command

Claiming that these things are “unnecessary concepts” is a significantly more extreme position than you make it seem. What are the alternatives that actually work?

see the entire field of anarchism for instance, Francis Ford Coppola even has a new movie coming out that draws directly from the works of David Graeber and Wengrow who have written on your kind of anarchy101 level question. I recommend trying wengrow and graeber’s Dawn of Everything or their academic papers. Understood it’s extreme to you. The writing’s there if you have the want to see it.

“We live in capitalism, its power seems inescapable – but then, so did the divine right of kings. Any human power can be resisted and changed by human beings.”

However besides just sharing that Graeber and Wengrow have documented realities in human history that explored answers to your question (and post discovery of agriculture, and scaled beyond dunbar's number), I'll also share this alternative response from Graeber's earlier works that predate a lot of the really exciting anthro and archaeological discoveries in recent years (the cutting edge research covered in their last book and papers):

“Normally, when you challenge the conventional wisdom—that the current economic and political system is the only possible one—the first reaction you are likely to get is a demand for a detailed architectural blueprint of how an alternative system would work, down to the nature of its financial instruments, energy supplies, and policies of sewer maintenance. Next, you are likely to be asked for a detailed program of how this system will be brought into existence. Historically, this is ridiculous. When has social change ever happened according to someone’s blueprint? It’s not as if a small circle of visionaries in Renaissance Florence conceived of something they called “capitalism,” figured out the details of how the stock exchange and factories would someday work, and then put in place a program to bring their visions into reality. In fact, the idea is so absurd we might well ask ourselves how it ever occurred to us to imagine this is how change happens to begin.”

Cool theorizing; but just one example of a current society that has flourished using no private ownership, please?

No current societies are anarchist no. See ya

Typical!

So you have zero evidence (aka much stronger true believer) of what you say working and you want to restructure the world based on fairy tales spun by the likes of David Graeber?

See ya.

Twitter in a system without private ownership: you stay up late in your attic with a flashlight, writing your tweets on a smuggled typewriter. The next day you hand them over to a high-ranking colleague at work who has access to the copier, whom (you hope) you can trust with your life.

Come now, thats unfair and unrealistic. Likely, you get thrown in a gulag for not possessing the license to tweet.

https://en.wikipedia.org/wiki/Censorship_in_the_Soviet_Union

Yep, this would never happen in a system without private ownership.

As such a system would never give rise to Twitter in the first place (hence problem solved).

Or such a system will forever reside in the Platonic ideal universe forever avoiding any real-world flaws or criticism.

citation needed

maybe you can disclaimer your post that you have the perspective that “By the time we exhaust Earth, we will be a space faring species.” You have a true believer's faith in the current thing

May be place a disclaimer first you don’t believe in real world evidence?

We are all true believers. I believe in a system that has real-world evidence of working and has some flaws that can be fixed over time.

You are a true believer in a system that has scan real-world evidence of working (but a lot of cool armchair theories) and you believe in throwing an entire system in favor of yours.

Btw, good on you for looking up my post history, you did more evidence-finding work than David Graeber ever did ;)

Not at all, you don’t understand the anarchist position if you say that