Assuming a trustworthy government with an independent legal system, all communication should be accessible upon judicial decision. This is analogous to acceptance of search warrants and seizure of evidence including paper based documents and messages.

Then again governments often aren't trustworthy. Germany isn't even able to issue European Arrest Warrants as prosecution here is politically dependent¹. And accordingly I also kind of prefer to have my electronic communication cryptographically protected. But I'm not so naive as to believe that this is a solution. This is just treating a symptom which eventually gets worse if not addressed directly.

1: https://www.eurojust.europa.eu/news/landmark-ruling-european...