In Pride and Prejudice, love is not a necessary component of marriage. In fact, most of the marriages we see are not based on love, but instead either on lust that quickly fades or on economic necessity. In this novel, romantic love is a privilege that most people have to do without and something that most people do not expect to find. At the same time, because love is a union between empathetic minds, it is shown to be a completely special emotion that is available only for intelligent, mature adults – it's the crowning achievement in the building of character.
Even though Elizabeth finds in Pemberley a confirmation of everything good and true in Darcy's character, she is also very much swayed by its wealth and privilege.
The Bennet children, even Jane and Elizabeth, are doomed to repeat the mistakes of their parents when it comes to their long-term relationships.