any particular individual would be likely to make more
Could this result be explained simply by people joining the workforce at a low wage, working their way up the ladder over the course of their career, and then retiring with a higher wage? If that's all that's happening here then it wouldn't seem to contradict the stagnation narrative at all.
But how would we find out whether that hypothesis is correct? And in fact what are the alternative hypotheses?
Even better would be to use more of those omitted variables: age, education, time in the workforce. One could use the General Social Survey for a rough take, using this link. I'd be curious to see the analysis if you'd like to do it.
ETA: The table linked by Landsburg has been called into serious question by Evan Soltas [H.T. CronoDAS]. I edited the post to leave only the table to provide context for the comment discussion of its status.
Economist Steve Landsburg has a post [H.T. David Henderson] about the supposed stagnation of median wages in the United States in recent decades. In the linked table median wages have risen for: