Marketing is important for several reasons. Let me list three of them.
First, marketing is important, because we live in a very competitive society. So, all companies are competing against each other to gain and retain customers. In light of this fierce market, marketing is important to gain an upper-hand if possible.
Second, marketing allows a company to know what the customers want and how they want it (for example, price point). This insight makes a company more profitable. A marketing company may also forecast what the new products will do well in the future.
Third, marketing is important also from an internal perspective. It allows the company to change it structure to become more efficient. This also allows for a competitive edge.