Child abuse, terrorism, drug trafficking and professional crime in general is a needle in a haystack compared to boring petty crime let alone normal communication.
Law enforcement entities that try to prosecute these kinds of crimes doesn't do it by building haystacks of data and then combing through looking for needles because that's a waste of their resources relative to the amount of results obtained. They do it by attacking the endpoints where the abuse or terrorism, or other professional crime has to actually happen. They find a terrorist, or a child abuser or a drug trafficker or they find evidence of their handiwork and then work from there. They see where they get their money, their bombs, their drugs, etc, etc and follow the links as much as they can. When law enforcement is actually trying to target crime they don't go fishing, digitally or in meatspace because that's not an efficient way to obtain results if the goal is to go after some genre of professional/organized crime.
Running a mass operation with no specific target (like speed traps in meat-space or dragnet operations in the digital world) is great for padding stats because you can say "look, we got X pounds of meth off the street" or whatever but it doesn't actually do much to target the professional crime because professional criminals take steps to avoid being caught in lowest common denominator type policing.
Neutering encryption (so that cops can continue to run surveillance dragnets) doesn't do anything to help the cops catch real criminals, that's just a talking point made up by the people who want the government to have the ability to put any arbitrary person under a microscope.
Law enforcement entities that try to prosecute these kinds of crimes doesn't do it by building haystacks of data and then combing through looking for needles because that's a waste of their resources relative to the amount of results obtained. They do it by attacking the endpoints where the abuse or terrorism, or other professional crime has to actually happen. They find a terrorist, or a child abuser or a drug trafficker or they find evidence of their handiwork and then work from there. They see where they get their money, their bombs, their drugs, etc, etc and follow the links as much as they can. When law enforcement is actually trying to target crime they don't go fishing, digitally or in meatspace because that's not an efficient way to obtain results if the goal is to go after some genre of professional/organized crime.
Running a mass operation with no specific target (like speed traps in meat-space or dragnet operations in the digital world) is great for padding stats because you can say "look, we got X pounds of meth off the street" or whatever but it doesn't actually do much to target the professional crime because professional criminals take steps to avoid being caught in lowest common denominator type policing.
Neutering encryption (so that cops can continue to run surveillance dragnets) doesn't do anything to help the cops catch real criminals, that's just a talking point made up by the people who want the government to have the ability to put any arbitrary person under a microscope.