I get the frustration here, but it's also kind of... idk? A “No, you just don't understand!” response. Everyone who works in a white-collar job knows what it's like. Everyone has different theories about why that project failed, but nobody knows the objective truth. Nobody can present a “documented and verified” list of reasons for why the project failed, not even the lead designer here. They can guess, but never reach the truth. He could repeat what he always did without changing anything in the next project, and succeed due to different circumstances, plain good luck.