Final answer:
The unique feature of an oligopolistic industry is mutual interdependence among a few firms with high barriers to entry. These firms' actions are closely linked, affecting each other's strategies and market outcomes. Significant barriers to entry allow oligopolies to maintain long-term profits and influence the market substantially.
Step-by-step explanation:
A unique feature of an oligopolistic industry is mutual interdependence. An oligopoly is a market structure where a few large firms dominate the market. These firms are interdependent because the decisions of one firm directly influence the strategies and profits of the other firms in the oligopoly. For example, if one oligopoly member changes its price or output, the others are likely to respond by changing their prices or outputs as well. The existence of oligopolies is often due to significant barriers to entry, such as patents, economies of scale, or government regulation, which prevent other competitors from entering the market easily.
Oligopolies may engage in collusion to set prices and outputs similar to a monopoly, sharing the profits. However, when competitive rivalry exists within an oligopoly, it can lead to differentiation of products or services to gain a competitive advantage. The presence of high barriers to entry and the potential for long-term profits characterize oligopolies, where firms do not usually produce at the minimum of their average cost curves, possibly impacting innovation and service quality without vibrant competition.