What does it mean to be competitive? I've asked students for years to (1) pick a company and (2) tell me about the market structure it is in and (3) tell me how competitive it is. Almost every class has a good portion that describes their chosen company as being a monopoly or perfectly competitive - even though those two market structures are relatively rare.

Usually, they choose companies like Wal-mart or Microsoft or Google and call it a monopoly (which none of them are).

-or they'll pick Coca~Cola or Pepsico and call it perfectly competitive firms?

Do perfectly competitive firms morph into something else?

What happens to monopolies? Do they just disappear?

Pick a firm that was the first of its kind (a temporary monopoly) and describe how it ceased to be a monopoly.

Or

Pick a firm that was one of many firms in a competitive industry and describe how it became less than perfectly competitive.