The American operations in the middle east have been largely successful in preventing further terror and making the country a safer place. There have been no terrorist attacks in America after 911. A lot of attempts at terrorism have been foiled. And, most of all, bin Laden has been found and killed. Clearly, the operations have been successful.
Yes, the United States has been successful in their efforts after September 11, 2011. With the exception of the Boston bombings, there has not been a major terrorist attack in the United States since September 11. The Boston bombings were not headed by Al Qaeda, so it is unfair to say that they were a result of a failure of post-September 11 policies.