Why the waterfall model of the software development process is not an accurate reflection of the software development activities?

The waterfall model of software development is often criticized for its linear and sequential approach, which fails to accommodate the iterative and dynamic nature of real-world software projects. In practice, requirements frequently change, and feedback loops are necessary for refining features, making it difficult to adhere strictly to the waterfall phases. Additionally, the model does not effectively address overlapping activities, such as design and testing, which often occur simultaneously in agile practices. This rigidity can lead to delays and increased costs when changes are needed late in the development process.