I think it's a bit more complicated. Most of Spider-man's Rogues Gallery are either working class themselves or else scientifically trained. With the exception of Kraven I'd say they're all possible futures for Peter that he needs to avoid.(*) Then Peter goes to college, starts associating with Harry Osborn and Gwen Stacy, who are from a wealthier background than he is; and both Gwen and Harry's fathers turn up. So when Norman turns out to be the Goblin he is being presented as another possible future for Peter to avoid.
I think that at the time it was written, upward mobility for first-generation university students was still a plausible aspiration or at least more plausible than it is at the moment. Norman isn't presented as having a qualitatively greater level of wealth than George Stacy and J Jonah Jameson.
(*) Only about half of them are animal themed. If you think that the majors are the Sinister Six and the Green Goblin, less than half, and that's counting Kraven.