"The Department of Homeland Security had asked for a two-year extension due to concerns that anything less wouldn't create a realistic chance of successfully meeting the deadline. "We truly believe we can have all the issues resolved in two years," says Homeland Security spokesman Bill Strassberger. "The chance of having them all resolved in one year is small." - eetimes.
There are doubtlessly many reasons for the delay, but those of technology and privacy are likely to be top of the list.