If they have those admirable middle class traits were they born that way? Or is cultural and social inheritance as influential as genetic inheritance?

I used to live in an upper middle class area, and a worrying number of the people were very polished thieves. They spent an unholy amount of time fighting over inheritances with other family members and over property boundaries with neighbours. When they worked - inevitably as land owners, landlords, upmarket real estate agents, investment advisors, lawyers, company directors, horse breeders, and so on - they'd always pad their bills and expenses, inflate their prices, and cheat on their taxes.

Were they "successful" - in the sense of being very comfortably off? Of course they were.

Did they try to marry their own? Naturally - out of snobbery and opportunism if for no other reason.

Were they admirable human beings or truly productive members of society? Not noticeably. Between the drink and drug problems, the predictable infidelities and ensuing dramas, and the polished and educated facade hiding feral greed and entitlement, they looked good from the outside - not so much from the inside.

If you don't own shares/stocks to any significant extent your labour goes to supporting these people. They make a lot of money from "investments" and pretend this is a glorious, noble, and risky social service. In fact they're simply skimming money from the top of the economy into their own pockets - effectively wasting it when it could be put to work doing something innovative for future generations.