It turned into a massive shambles because the main players - the New York Port Authority and Larry Silverstein who is the developer - have spent years wrangling over the design, amount of office and retail space etc instead of getting on and building it. It got so bad that the Mayor stepped in and demanded some action. He said it was an insult to the victims of the attack that there was still no official memorial in place - the Pentagon memorial was finished some time ago. They have now promised that the memorial will be ready for the 10th anniversary but a lot of New Yorkers are not holding their breath. The final design has also been dumbed down considerably.