Exactly, Argentina and many other declining states find that from one generation to another the changes are persistently negative, but it becomes harder and harder to realize what has been lost unless you have a reference point - for instance, would East Germany have looked that if it were not sitting right next to the prosperous West Germany?

What we might find (one possibility) is that we slowly slip into a decline that we can only diagnose long after the fact when it might not be fixable.

If you haven't read Jared Diamond's "Collapse", I highly recommend it. Not all Collapses are the same. Some take weeks, some take years, some take many generations.