That’s a toughie, isn’t it?
I am not sure that I agree that voting is a bad way to handle things when the group is of an arbitrarily large size.
I am also not pushing that everyone make all decisions; I am indeed a fan of specialization within fields. This would include project management.
I do not feel that a project manager or managerial team requires an elevated power position to accomplish their tasks.
Well, but as soon as you introduce a project manager, you’ve got a hierarchy, because the manager has influence over the other members of the group. It is his or her job to make decisions when the members of the group argue, and they have to accept his decision, which gives him or her authority over them.
Voting is problematic in large groups because of the time involved to vote on issues. If you have a group of 100 people, and any disagreement between any two people needs to be put up to a vote, you will in likelihood spend most of your time voting.
I was trying to stay within the bounds of the OP which was much more general than your scope.
Hierarchies can be used to value people as objects based on their contribution to the goals of the group rather than working to most effectively use the skills of the individuals so that they all obtained their full potential. This is not however necessary even for class based structures. I would view a bee hive as an egalitarian class hierarchy, all members work towards there own personal happiness which just happens to be the need s of the queen and the propagation of the community. This is one of the few structures I know of where all members are equally satisfied, and is not one I want to emulate.
As I said history has shown that in the long-term societies that mismanage the costs they impose verses the benefits they provide eventually prove unstable, and are thus self-correcting. If your question is can short-term remedies to this inbalance be established? My answer is that we are still working on this, and have yet to come up with a model that does not tend to degenerate eventually.
And to add the Captain Amazing arguments what if the two people are not equally qualified to make the decision, what if one person has no knowledge of the issues and is making an objectively incorrect decision, but can not be convinced of such?
Egaliterian human societies break down because not all members are equal, some are distructive and counter productive some are only required in special circumstances, others are sure that they are differnt and deserve spiecal treatment. It would be nice is this were not so, but this is the way we have currently evolved and hence our strucures tend to represent this.