What causes many software project failures?

Increasing system complexity is indeed a significant factor that contributes to many software project failures. As projects grow in scale and complexity, managing the various components, dependencies, and integrations becomes increasingly challenging. This complexity can lead to misunderstandings among team members, difficulties in communication, and complications in implementation and testing.

Complex systems often require more sophisticated design and architecture, which can lead to misalignment between the technical requirements and the end-users' needs. Additionally, higher complexity can increase the chances of bugs and defects, making the software harder to maintain and extend. Therefore, projects that involve sophisticated requirements or complex interactions are at higher risk of failing if not managed properly.

The other factors listed, while they can also contribute to project difficulties, do not encompass the systemic challenges posed by complexity in the same way. For example, negligent coding practices may lead to poor quality software, but such issues can often be mitigated with good practices and a disciplined approach to software engineering. Lack of resources affects project viability, but a well-resourced team can still struggle if the complexity of the project is beyond their capabilities. Insufficient user feedback can hinder a project, yet the core issues arising from complexity are often more fundamental and pervasive, affecting all aspects of a software development effort.