I’ve just read a great and insightful article on Wired about the development of a game that was never finished and it was canceled after 12 years of development. The game is Duke Nukem Forever and the article is called: Learn to let go: How success killed Duke Nukem
The situation from the article happens often when there is no direction, no milestones, no plan. If the plan is that there is no plan, then the project will certainly fail.