Final answer:
The I/O model emphasizes industry structure as the key determinant of a firm's profitability, making the claim that uniqueness of resources is the main source of above-average returns false.
Step-by-step explanation:
The assertion in the question is false. The I/O (industrial organization) model does not primarily focus on a firm's unique resources and capabilities as the main source of above-average returns. Instead, the I/O model emphasizes the importance of the structure of the industry in which a firm competes.
According to the I/O model, factors like how a firm is positioned within the industry, the level of competition, and the bargaining power of buyers and suppliers are key determinants of a firm's profitability and potential for above-average returns. On the other hand, the resource-based view (RBV) of the firm suggests that the uniqueness of a firm's resources and capabilities is central to achieving a competitive advantage and, thus, above-average returns.