If people agree to "manage" something, you'll end up with something that acts very much like a <scarequote>government</scarequote>.
The issue with talking about "anarchy" is that it's very easy to slip into semantic word games instead of looking at the underlying concept of how humans behave.
One reason "governments" or "managing" happens is that the real world has finite resources that's simultaneously desired by multiple people. E.g. there's a desirable piece of land. Since more than 1 person wants that land and since multiple can't live in the same spot, a conflict occurs. This eventually leads to a subset of people that make rules for others to follow. Whether you call that subset a "government" or "leaderless anarchy with unacknowledged rule-makers (wink)(wink)" is academic. (This is related to the joke, "we are all equal but some are more equal than others.")
If we depend on abolishing the idea of "property" to support the implementation of "anarchy", it still devolves to semantic word games because humans will invent equivalent euphemisms to "ownership" such as "99-year leases" or "temporary stewards of this land as communicated by a God", etc. Whatever people decide to call the control of that land, it's functionally equivalent to "property ownership".
This "resource limit" pattern repeats itself in the digital realm. Theoretically, there can be 7 billion people each with their own cryptocoin of which mad_tortoise_coin is one. However, these 7 billion individual blockchains are not useful. On the other hand, if people want to converge on a single blockchain cryptocurrency (such as Bitcoin) with stable attributes, a governance model will have to emerge. There's no way around it. If we still insist that we can have "anarchy" in Bitcoin because people can fork it, you eventually get "governance_0002" emerging in bitcoin_fork0002. Nobody "owns" the entire Bitcoin blockchain but nevertheless, participants still want to own pieces of it via public/private key pairs.
The collection of behavior that trends into a <group> that's functionally equivalent to something called "government", and a <concept> that's functionally equivalent to "ownership" seems to be embedded in the human condition.
> These all can be managed without government should the people want it
You say this as if the predictions of a social theory are as reliable as those of Newtonian physics. I don't think they are. And because I know of no historical example of an industrialized society functioning sustainably without a government, I tend to doubt a theory that says it's possible. Because if it was, you would think somewhere, somehow, it would have been successful already.
Governments can only not exist when the population density is so low that people only interact when they want to and can cease interaction when they so desire. This is extremely low population density, and given the increased range technology gives us, there are very few places that have this low of a density, and even then it only lasts as long as the density doesn't increase due to some migration event.