The trope of inferiority shows up in literature writen about emperors by their near contemporaries.

The most noteable example is in Pkutarch's Life of Julius Caesar, in which Caesar weeps when he realizes that, at his same age, Alexander had already conquered half the known world. He turns that grief into anger, and it helps fuel his drive to take over the Roman Republic.

This comparison between Alexander and Julius Caesar is a pattern in Plutarch's history writing - he wrote a number of biographies that compared a Greek leader from the past to a Roman from more recent history. Some comparisons are more balanced than others (he doesn't suggest that all Greeks were better, or vice versa), and the point of the exercise seems to be that the past is a useful tool for understanding more recent events (and also, prhaps, that Rome and Greece have a lot in common).

In practice, Romans were very conscious of their history, and they were very capable at comparing themsleves to their past and their neighbors. The comparisons, just like those made today, were sometimes favorable and sometimes negative, depending on the person making them and the goal they were trying to accomplish (ie critical social commentary vs self congratulation).