Almost all of the apps you mentioned sync data to, or access data from iCloud in the vast majority of use cases. I mention iCloud here because this submission is about iOS.
replyThat said, I'd love to have a new "Internet access" permission for apps, so users had the choice. Perhaps even separate "Allow iCloud" and "Allow Internet" but that's probably too granular for Apple's taste.
For that case, iOS could just run a system daemon to shuttle the app data to/from iCloud. The app itself should not need internet access for this.
replyI have no idea if this is what already happens, but I feel like it might be. (Why would each app have all these network connections when the system could just manage it instead?)