A firm in the market economy survives by producing goods and services that persons are willing and able to buy. Consequently, ascertaining consumer demand is vital for a firm's future viability and even existence as a going concern. Many companies today have a customer focus (or market orientation). This implies that the company focuses its activities and products on consumer demands. Generally, there are three ways of doing this: the customer-driven approach, the market change identification approach and the product innovation approach.
In the consumer-driven approach, consumer wants are the drivers of all strategic marketing decisions. No strategy is pursued until it passes the test of consumer research. Every aspect of a market offering, including the nature of the product itself, is driven by the needs of potential consumers. The starting point is always the consumer. The rationale for this approach is that there is no reason to spend R&D (research and development) funds developing products that people will not buy. History attests to many products that were commercial failures in spite of being technological breakthroughs.
A formal approach to this customer-focused marketing is known as SIVA (Solution, Information, Value, Access). This system is basically the four Ps renamed and reworded to provide a customer focus. The SIVA Model provides a demand/customer-centric alternative to the well-known 4Ps supply side model (product, price, placement, promotion) of marketing management.

The extent to which what customers say they want does not match their purchasing decisions. Thus surveys of customers might claim that 70% of a restaurant's customers want healthier choices on the menu, but only 10% of them actually buy the new items once they are offered. This might be acceptable except for the extent to which those items are money-losing propositions for the business, bleeding red ink. A lesson from this type of situation is to be smarter about the true test validity of instruments like surveys. A corollary argument is that "truly understanding customers sometimes means understanding them better than they understand themselves." Thus one could argue that the principle of customer focus, or being close to the customers, is not violated here--just expanded upon.
The extent to which customers are currently ignorant of what one might argue they should want a which is dicey because whether it can be acted upon affordably depends on whether or how soon the customers will learn, or be convinced, otherwise. IT hardware and software capabilities and automobile features are examples. Customers who in 1997 said that they would not place any value on internet browsing capability on a mobile phone, or 6% better fuel efficiency in their vehicle, might say something different today, because the value proposition of those opportunities has changed.