I'm aware of how decision-making works, but thanks for that brief summary
pragmatically past a certain point of complexity - though, a higher one than I'm sure you'd think - some kind of hierarchy becomes inevitable
for one, you're assuming that complexity is desirable
also, collective decision-making is not "everyone do their own thing". it's everyone decides what should be done.
and, I'm not saying it's perfect or without difficulties
in fact, having experienced it, it's often a huge pain in the ass
I led a national 'members association' for three years which had been created to represent all members' interests equally.
The members were generally not interested in shaping policy directly - unless we moved in a direction contrary to their interests.
How do elicit what they want? By asking them, requesting input, setting up working groups, votes, electing people to the Cttee from their number etc.
Some decisions were most appropriately made by vote; others involved specialist or confidential knowledge - the members' input in those decisions was at one remove: they elected people who they felt would be best able to deal with those situations.
My role was to ensure that the members' interests were always represented in decisions made by the executive layer (who often had their own agendas), as well as give direction to - and, crucially, coordinate - the executive.
The ideal is to get everyone on side, moving together in a positive, morally acceptable direction.
It's also crucial that the executive be in a fundamentally fragile position - that the members can eject them if things start going obviously awry.