This is a valid question. In some cases it has to do with the amount of data you're working with. Most database management systems have made progress for aggreg

This is a valid question. In some cases it has to do with the amount of data you're working with. Most database management systems have made progress for aggregating large amounts of data. In many cases it is still necessary to distribute the workload, which in turn creates the need to build out the rest of the distribution system. With that being said, and to your point, I would not be surprised if these systems were often over engineered when a sql query could get the job done.