The trite answer, of course, is that everybody does. But look around your own organization. For IT projects of any consequence, I'll bet one finger of blame is being pointed at someone for every five lines of project code Answering this critical question realistically requires a look at three different issues.
Every project involves a degree of complexity.
Products keep missing performance targets. Compatibility issues prove difficult to resolve. People make ill-informed choices daily. There s no limit to the number of annoyances that creep into the everyday activities of getting things done. Requirements are what make the second issue the issue of ownership so very, very important.