If an app is good enough, developers and managers and "agile coaches" and such don't stop, they start doing busywork. It looks like they're working and progressing, but all they do is scare users away with by removing features, breaking workflows and more horrible stuff. You're just making money for the shareholders, nothing more. They don't care about users...
In the case of many popular apps, it's a bit more than that: they're actively fighting what they perceive as bad actors, that is people trying to use their app not as intended, using their protocol outside of the official app and so on. In this case they have nothing to gain by describing the changes in more detail in the changelog.
