Plans are only good intentions unless they immediately degenerate into hard work.
I have worked with many companies dissecting failed launches and Business Cases gone awry. I've also had my own share of product performance issues during my tenure as a product manager and as a product team leader. Along the way, I've built up a repertoire of reasons why products might fail to perform in the market or miss their financial objectives. You can also find, among the vast amount of literature written about New Product Development (NPD) and why products fail.
One of the most frequently cited root causes of these problems seems to be ...