> Not only were humans very loosely hierarchical essentially until the invention of agricultur

Even if they were both this and peaceful then, this would only imply that we merely need to dismantle agriculture and the civilization dependent on it to return to that state, which I submit is an unacceptable trade-off to most people.

And even if it was acceptable to most people, it would take only a small minority opting out to retain the power to subjugate everyone opting-in and ruin the whole effort.