Final answer:
The decline stage of the product life cycle leads to products eventually exiting the market. Companies innovate to stay competitive, leading to the discontinuation of older models. This cycle of product development is intrinsic to the modern product market.
Step-by-step explanation:
When a product goes into the decline stage of the life cycle, it eventually exits the market. This happens because companies must continually update and "improve" their products in order to stay competitive. Designers and marketers are tasked with innovating to stimulate consumer interest and prevent stagnation in sales. However, this demand for innovation can lead to the discontinuation of older product models as new ones replace them. For instance, if you have a favorite toothbrush that wears out, you may not find the same model available again because it has been superseded by a "new and improved" version. This cycle of continual product development and obsolescence is a characteristic of the modern product market.
The life cycle of a product is much like the life cycle of interest groups, going through stages of creation (or birth), growth and change (or evolution), and sometimes death. The consumer treadmill phenomenon is a result of this life cycle, as it encourages consumers to replace products more frequently than they might otherwise, leading to a cycle of purchasing that supports manufacturing and economic growth.