Nothing is 100% effective, and there will always be a long tail and diminishing returns on any economic organization, such as the NSA.
Additionally, there are simply too many unknowns to say that they're not doing a good job, and I think that's the nature of intelligence work. Lots of secrecy makes oversight and external efficacy judgments difficult to make; there's just not enough data.
It's like trying to say that a chess player is doing poorly when you don't know the size of the board, the number or types of pieces on either side, the positions, or really anything but an incomplete glimpse at the captured pieces of both sides. And they don't want you to see those pieces either, so even that is probably incomplete.
Additionally, there are simply too many unknowns to say that they're not doing a good job, and I think that's the nature of intelligence work. Lots of secrecy makes oversight and external efficacy judgments difficult to make; there's just not enough data.
It's like trying to say that a chess player is doing poorly when you don't know the size of the board, the number or types of pieces on either side, the positions, or really anything but an incomplete glimpse at the captured pieces of both sides. And they don't want you to see those pieces either, so even that is probably incomplete.