Why do IT projects fail?
I am sure if you ask that question to ten people you will get 10 different answers, or at the very least a wide variety of reasons. The product chosen to deliver the solution was a poor match, the product was implemented incorrectly, the PM sucked, the Vendor gave no support, insufficient training material/resources, poor interoperability, the list goes on and on.
One issue I have observed from time to time on my travels is quite different from the above listed examples.