Except for the perfectly ordinary meter (like that of "Clementine"), I don't see any similarity in text or tune or theme between "The Gypsy's Warning" and "Poor but Honest."

What am I missing?

According to Ed Cray, the "Clipper" song is much more recent parody of "Poor but Honest."

Auden's claim that "PBH" is a "Victorian ballad" seems to be based on intuition alone.