all three of these songs sound incredibly similar to eachother. like, a ridiculous amount. same key, similar melodies, and christ, glory days is basically just cocaine socialism minus the horns
The backing track for "Cocaine Socialism" was originally demoed as "Northern Souls" in 1996. It was then recorded again during the album sessions and considered as their comeback single in 1997. Jarvis then "bottled it in the end and rewrote it as Glory Days". The title was changed to "Cocaine Socialism" when they released it as a b-side to "A Little Soul" to avoid confusion over the titles. So that explains the similarity between those two.
As for "Common People", yes, they are similar but I think that's more coincidental. There are other Pulp songs that are similar to each other i.e. "They Suffocate at Night" and "Live Bed Show" (replace "his body loved her" with "This bed has seen it all"). Also, the chords from "97 Lovers" were re-used in "OU".
I always felt that it was deliberate. Because Cocaine Socialism was their comment on politics in Britpop, so they kind of wanted the listener to be thinking of their popularity so why not make something similar to their biggest hit?. And then when it became Glory Days they didnt hide the similarity they used to play it at the end of sets and turn it into Common People to end on.
Common People and Glory Days / Cocaine Socialism have that "spoken words" verses that are typical for Jarvis. To me they are half a song, half a story or social commentary more than a song. the melody isnt exactly the same though, so technically, they are not the same song.
But the magic is there. They managed to make 3 different songs with the same structure. That's genius if you ask me.
A lot of pop songs are based around the same chords changes. But when you dig into the melody, there are vast differences.
I'd be interested to hear what Glory Days might sound like if it'd been produced by someone else, without the Chris Thomas bludgeoning-wall-of-sound technique that worked so well on Common People.