Where'd my social status go?

In Western societies, social status of an individual is determined mainly by her job. Naturally, the perceived status of a job is correlated with income and education it requires, though not perfectly: college professors are better educated than corporate CEOs and New York City waste collectors make about the same as New York City firefighters, for example. What's interesting to me is that some jobs change their social status over time, sometimes dramatically. For example, over the past few decades, the jobs of a high school teacher, postal worker, flight attendant or airline pilot lost a great deal of their (initially very high) status. The job of a film actor, on the other hand, moved from extremely low to extremely high status over the first fifty years of its existence. I don't know what causes these shifts or if the causes are uniform. Just pointing out the obvious.