I think these are different. They mostly find vulnerability in the iOS system as opposed to try to crack the backup system.

I think iOS or Android backup system are rather secure compared to other components because of the following: hacker will also need to break into a cloud drive to retrieve them, which adds extra work; the backup is simple, just bunch of files and a password, apple/google can use standard well-tested encryption to encrypt them.

However, guaranteeing there is no way to break into an operating system, especially with all the features that a modern system requires, is much harder.