What should have been a glamorous and career-capping commission for the 63-year-old Spanish architect, the new transit hub at the rebuilt World Trade Center, has instead been plagued by extensive delays and massive budget overruns. In the end, it will likely take roughly twice as long to build and cost twice as much ($4 billion versus $2 billion) as originally planned. In the process, it’s become a symbol of larger bureaucratic problems at Ground Zero, a money pit half-buried next door to the National September 11 Memorial and Museum.