Final answer:
In the hierarchy of substitute decision makers, when collaboration costs are too high and no consensus is available, the group defaults to the 'status quo', meaning no new decision is made and the current situation continues.
Step-by-step explanation:
When discussing the hierarchy of substitute decision makers and what happens when the costs of making a collective decision become too high, it's essential to understand the implications of a breakdown in the decision-making process. In such cases where a large group, such as 300 people, cannot agree on a common decision, like where to eat, the process can become impractical due to the immense effort and time needed to reach a consensus. If this dilemma persists and no alternative decision-making method, such as majority rule or delegation, is available or viable, the group may default to the 'status quo'.
The status quo is essentially what exists or happens if no new decisions are made. In the context of the substitute decision-making hierarchy, if no suitable decision maker can be identified or no agreement can be reached, the current situation continues unchanged. When applied to the restaurant example, this means that without a decision on where to eat, no one would be going out to a restaurant at all, and the last option in the hierarchy of decision makers would not be utilized.