That decision-making model might not work in your company if some of your coworkers are worthless. There's always the one person in every meeting who keeps changing the topic, or doesn't understand the issue, or insists he knows more than he does, or is bluffing to cover his ass, or is jockeying for a promotion, and so on. To put it in clearer terms: Management exists to minimize the problems created by its own hiring mistakes.
Scott Adams comes at this from the perspective of a small startup, but once the group of people involved have differing visions, I would say having a hierarchy makes someone accountable for having the right vision.
Though I'm still not sure if I actually disagree with his point...