In a way, it reminds me of the CIA after the 1979 botched Iranian hostage rescue, when they decided that having agents on the ground in foreign nations was too dangerous. So the focus became remote observation. But seeing $OPPONENT has 100 bomber planes is different from hearing $OPPONENT’s leaders discussing an invasion before it happens.

In the same way, police must replace their dependence on intercepting communications with good old fashioned police work. Talking to people, asking questions, saying “$PERSON’s story sounds fishy, maybe we should pay a little more attention”.