There is not always a solution to a problem.
Let's say you wanted to bring the number of car crashes to zero. Eventually there's nothing 'reasonable' left to be done, and the only remaining option would be to ban cars altogether. Instead, we accept a certain number of crashes because it's deemed more important to be able to drive a car than it is to bring the number of car crash fatalities to zero*.
For example, in a country like Germany there are 0.8 homicides per 100K inhabitants. You could put _everybody_ under surveillance, just to have an easier job of finding the perpetrators. In the process there would be many false positives, wrongful imprisonments, etc.
In order to preserve the rule of law, maybe it's sometimes best to accept that you cannot create the perfect society. At least not a society in which people who are innocent (the very vast majority) can also still enjoy their freedoms.
Besides, I feel like the police has become somewhat lazy in many Western countries for the past 20 years. Before the rise of the internet, it was simply accepted that you couldn't know what two spouses had said to each other and you had to rely on good-old detective work. However, since things like Facebook Messenger, the cops expect to be able to get a warrant for all this data. That era appears to be slowly ending with E2EE, and all of a sudden they're struggling because those detective skills have slowly deteriorated.
* To be clear, I think that in many countries there's still quite a lot of room for improvement to reduce the number of car crash fatalities. Not in the least in the USA.