Power BI developers ensure that data analytics solutions are scalable, allowing businesses to expand their data capacity as needed. They design data models that can handle large datasets and optimize performance by managing data sources efficiently. By integrating Power BI with cloud platforms like Azure, developers enable businesses to scale their analytics operations without significant infrastructure investment. This scalability ensures that as a business grows, its data analysis capabilities can grow alongside it, supporting larger datasets, more users, and more complex queries without compromising performance.