Wiretaps, postal interference.
None of it was routine, but the tactic for dealing with serious criminality was still there.
>Historically, you and I have always had options and methods of keeping our personal info and our private comms out of the reach of police, govs and other powerful actors. It was good for us and promoted a healthy society.
No you haven't. It is only until very recently that iPhones (less so android devices) have been basically uncrackable (notwithstanding NSA/GCHQ level tactics that aren't going to be used for criminal investigations) and, coupled with end to end encryption, you have a communications system for which their is no practical method of compromise.
It is very good for the citizen, but you cannot argue for it without also acknowledging that it is incredibly advantageous for the criminal. It is without precedent in human history.
I'm not saying that the police should be able to backdoor everything useful, because that's nonsense. What I'm pointing out is that once you realise that your suspects understand how to use signal and how to use a VPN and how to maintain some sort of operational discipline (and this isn't a high threshold), then your crimes become incredibly hard to solve even with a perfectly executed investigation and this is reflected in the clear-up rate.