True. In a healthy society, policing is hard.
> and it is also true that being able to operate a fully encrypted communication system makes it harder as you rely on mistakes.
Yes. You are describing actual police work; it is how things have always been.
Because this was true before robust encryption, we know encryption doesn't change the equation and can be safely omitted from your assertion.
> As we saw with Encro, criminal groups with Signal and modern iPhones can communicate with gay abandon if they maintain decent opsec.
Governments have never had realtime access to our communications. Humans' communications have been private for as long as there has been language. Privacy is good for us and is better than all other alternatives.
Robust encryption is how we maintain that natural, neutral, healthy default.
Otherwise, we're talking about gifting new, unprecedented surveillance powers to officials, politicians and their powerful allies.
Massive power. Over us. At which point we are less safe.