The Gardiners where if fact judged on their being in trade and the area of London in which they lived.Not their name! At the time Cheapside was an area for those who had made money in buisness but where still having to take an active role in the running of the buisness. Bingley though his father ( an probably grandfather) had made the money (from trade )he no longer had to be an active part in the buisness. He was considered a gentleman with no profession required to supporot the family.
Jane Austen is making fun of the Sisters who seem to have forgotten where they came from, they themselves have a identical background, but are further up the chain. But they are still nouve riche(new rich). Which means they are still not acceptable in some areas. Darcy is Family money, which means that the estate provides most of his funds, though some of it would still have come from other sources (such as a plantation as in Mansfield park) . the difference being that he and his father and grandfather did in fact rarly have to get their hands dirty with this work thing. Bingley is in fact an old English term .