Pride and Prejudice certainly reflects the social realities of its time, especially for women. Marriage was almost a requirement for middle-class young ladies to secure their future since they were not legally able to inherit property. Since their father's estate will go to their cousin, Mr. Collins, the five Bennet girls must marry, and preferably marry well.
Another social reality that the novel addresses is the notion of propriety. The fact that Elizabeth's family so often behaves improperly is a serious concern for Darcy, since behavior was considered the outward manifestation of inward morals. (The idea of having a "public face" to present to the outside world is much more modern). Therefore, Lydia's elopement with Wickham is a grave social mistake. The fact that Darcy is willing to help "fix" this disaster says a lot about his character and about his feelings for Elizabeth.
"Pride and Prejudice" faithfully reflects the social realities of the Regency Period (1811-20).
The contrasting lifestyle of different social groups is structurally central to a Jane Austen novel. In "Pride and Prejudice" the landed gentry represented by Darcy is contrasted with the newly rich trading class represented by Bingley.
The novel was written against the background of the threat of an invasion by Napoleon. The militia was a temporary voluntary force raised especially during times of a national emergency. Wickham was a member of this militia. Col.Fitzwilliam Darcy the younger son of an earl, on the contrary, is a fully commissioned officer of the regular army. In those days only an aristocrat or a member of the gentry could afford to purchase a commission in the army. In "Pride and Prejudice" Darcy purchases a commission for Wickham so that Wickham agrees to marry Lydia.
Jane Austen portrays only the elegant aspects of Regency England. The seamy side,however, is sometimes hinted at. Discipline in the army was very harsh and there is a report of a private being whipped. Similarly the prevailing poverty of the lower classes is revealed by the reference to poor feeding.
But most importantly the harsh reality of a bleak future for a dependent unwed old woman is hinted at when Charlotte Lucas' brothers are relieved that Collins is going to marry their sister, for otherwise they would have to look after her in her old age.