Source1 : too old to be useful
2 : older than is normal for one's position, function, or grade
Thank you for the clue. And thank you for asking a question about lyrics (especially from a Southern rock band ... which is a bit absurd to say to a Chilean, eh?). Lyrics are often loaded with double meanings and ambiguities. Thus they lend themselves well to speculation.In case it might help... The song is about people (men) who work on shifts, and also a sort of criticism of world powers.