The term consumer refers to the people that buy products and/or avail of services for their own use.
Consumers nowadays are more empowered than those that lived in the early 1900s when the production concept still prevailed. Before, it was the manufacturers that dictated what they would be making and how much. They thought that if they made enough products at a low enough cost then consumer demand will follow.
In the 1930s, when competition between manufacturers increased, the sales concept became more prevalent with manufacturers not only focused on production but also in advertising. This time they realized that consumers actually need convincing to buy their products.
After World War II, when the global economy got better, consumers became more selective. This meant that manufacturers needed to adapt, resulting in the marketing concept, which puts the needs of the consumers at the center of every business’ priority.
In order for manufacturers to be able to sell their products, they found that they not only needed to advertise, but develop products and services that meet the needs and wants of consumers, price it reasonably, make it accessible, and advertise aggressively. In short, the power shifted in favor of the consumers. Nowadays businesses know that to make a profit they need to make their consumers, now called customers, happy.
Consumer laws have also added to the shift in power since in many countries consumers are protected from unscrupulous practices. Companies that deliver inferior products and advertise falsely can be sued by unhappy consumers.