Which enable an oligopoly to form within a market? costs of starting a competing business are too high. the government restricts market entry. no competition exists between producers. econ

Oligopoly is slightly different from a pure monopoly. While a monopoly means that there is only one producer dominating the market, oligopoly refers to how a few companies dominate the market between themselves.

In today's world we can see examples of oligopoly all around us. For example, the dominance of iOS and Android software on virtually all smart phones around the world. The dominance of Walmart and Costco in the United States etc.

How these form can be due to a number of factors including high costs of doing business or even government legislation.

porter is writing economic history because he is focusing on the cost of developing vaccines.