During this Regency period the class system was a widely-accepted paradigm that consisted in that "the natural order of things" dictates that those born into wealth and name will remain that way and no opportunities would be given to others who might want to advance class-wise. The accepted idea was that this was the norm- the rich remain rich and the poor remain poor. The only way you would get out of it is by a shot of luck or by marrying into money. However, the lack of money would only get you as good a candidate as you can afford- this was the preocupation with the girls in Pride and Prejudice more than anything.
Darcy however embodies this validation. His constant banter on how he deserves great things because he was born into wealth and rank, and the fact that people understood and almost expected his behavior to be like that certainly validates the claim of the "natural order of things" paradigm which was an established mode of life during these days.