What is the marketing concept discussed in the passage?

To understand the marketing concept, it is only necessary to understand the difference between marketing and selling. Not too many years ago, most industries concentrated primarily on the efficient production of goods, and then relied on "persuasive salesmanship" to move as much of these goods as possible. Such production and selling focuses on the needs of the seller to produce goods and then convert them into money.
   Marketing, on the other hand, focuses on the wants of consumers. It begins with first analyzing the preferences and demands of consumers and then producing goods that will satisfy them. This eye-on-the-consumer approach is known as the marketing concept, which simply means that instead of trying to sell whatever is easiest to produce or buy for resale, the makers and dealers first endeavor to find out what the consumer wants to buy and then go about making it available for purchase.
   This concept does not imply that business is benevolent or that consumer satisfaction is given priority over profit in a company. There are always two sides to every business transaction--the firm and the customer--and each must be satisfied before trade occurs. Successful merchants and producers, however, recognize that the surest route to profit is through understanding and catering to customers. A striking example of the importance of catering to the consumer presented itself in mid-1985, when Coca Cola changed the flavor of its drink. The non-acceptance of the new flavor by a significant portion of the public brought about a prompt restoration of the Classic Coke, which was then marketed alongside the new King Customer ruled!