If you want to compare abilities, in the 90s you also didn't have Internet-connected cameras on every corner, or in public transportation, also able to do face recognition even with masks on, you couldn't use Wi-fi to see through people's walls, or to monitor the IPs a home connects to, etc.
As for iOS, there are always vulnerabilities that state-level actors can exploit. Not long ago simply sending a message to someone via iMessage could have compromised an iPhone. Which is why iPhones now have a "lockdown mode". Criminals are either dumb enough to expose themselves via insecure devices, or competent enough to use an extra layer of encryption, which can't be prevented. Even if you outlaw general-purpose computing, people can just send encoded messages with custom algorithms, WW2-style.
If you target someone specifically, and have access to their location, there's no way they can protect themselves while also keeping a communication channel open. Let's be honest, this isn't about targeting someone specifically, but about fishing for wrongthink.
> So what do we do?
As a citizen, not my problem. Law enforcement should do their jobs without encroaching on my privacy. Or my child's privacy for that matter.
If scientists invent a way to read people's thoughts, what next? Mass surveillance for people's brains directly because there's no other way?
If the question is mass surveillance, NO is always the answer as far as I'm concerned.