Tying Gatsby's conclusion to the long-forgotten opening paragraphs

Let's jump back to the beginning of The Great Gatsby. As noted a few days ago, probably not one reader in a thousand can quote the opening line - so much happens and there's such beautiful writing throughout this great novel that by the time we finish we don't exactly recall where it all began, and that's in part because the opening is prosaic and it involves advice that Nick Carraway's father gave to him long ago - and why should we remember? Nick's father has no role in the novel at all and is barely mentioned after the first page (if at all), and Nick himself is the perfect narrator but not a actor in the plot except as a go-between. Old sport, could've been anyone. The opening statement is advice from Nick's father: don't judge other people as they may not have grown up with the advantages you've had. Good advice - except that all of the major characters in TGG have advantages equal to or greater than Nick's: They're people of privilege, the right school, jobs, sports, clubs, clothes...so to that extent the advice is pointless, or at least beside the point. Why not judge your social equals? And Nick does - and finds them cruel and careless (and by the end we have to agree - Tom and Daisy skating off, leaving the wreckage behind). All are his social peers but one - the eponymous Gatsby. Now here's a guy who didn't grow up advantaged - he's self-made, left home to work the fishing fleets, takes on a job as crew mate on a yacht (owned by the mysterious Dan Cody - is he the one that introduced young Gatsby to a life of crime?), then goes into the army, does really well in the World War, promoted to major, and then - what happens exactly? It is and always has been a puzzle to me: If Gatsby's sole purpose in life is to win back his lost love, Daisy, why does he pursue a life of crime? Of course she is superficial and likely to be attracted by his great wealth, all of which proves to be a sham. But wouldn't you think Gatsby would have gone into stocks and bonds - like Nick - and made a fortune that he could call his own? But no - there's something completely perverse about him and in my view not typical of the self-made American hero. He's a criminal and a thug, just as repulsive a man as the cruel Tom Buchanan, certainly more repulsive than the Jewish gangsters whom FSG strews about the story: they, too, are guys who didn't have privileges, so let's not judge them (though FSG seems to judge them - while letting Gatsby off the hook - he's tragic, they're comic). Maybe Gatsby didn't deserve his fate, but it's with a sense of glee, or schadenfreude, that we, or at least I, watch his empty funeral and depopulated mansion. Nick's a good guy but why does he care so much for Gatsby? Because Nick is a romantic, I guess (his vision of returning home to Chicago for xmas, all the parties, the folks in his set largely taking over the train stations, the landscape - so confident, so protected, so naive).