Final answer:
Some reasons why new businesses fail within the first five years include poor management, unproductive workers, tough competition, and shifts in market demand and supply. However, bad luck is not a common reason for business failures.
Step-by-step explanation:
In the model of perfectly competitive firms, there are several reasons why new businesses fail within the first five years.
These include poor management, unproductive workers, tough competition, and shifts in market demand and supply.
However, bad luck is not a reason many new businesses fail within the first five years.