I'm certain one of the reasons is that all kinds of things were selected, before getting to the meet of the requirements. Which is typical of large government IT projects, where the order is often: choose some of the technology stack, write an contract opportunity (RFO, etc.) around the chosen technology and a vague (even if stated in terms that seem precise) concept of the requirements, select a contractor, who then pre-determines more of the tech stack based on their own offerings, business relationships, or competencies, then starts gathering real implementable requirements and building the customer-specific elements of the software (and even the last two are sometimes in the reverse order.)
