Anarchy is not something that was ever meant to work in and of itself. It is an ideological direction against structural concentrations of power. We're somewhat talking about same things here with different semantics. Now, we could go deep into debate on how to define hierarchy, but I think it's easier to agree that we can't fully eliminate concentrations of power from society. My idea of anarchy is moving and promoting towards dimishing these concentrations of power. As to how would be yet another whole, more complex and multi-dimensional, topic.