Mansfield Park: Theme Analysis

Fanny’s sense of duty colors this novel and she stands as an exemplar of sorts of femininity. She performs the role of the dutiful impoverished niece well and is rewarded by the end with the marriage of her choice: to Edmund. The women who do not conform to societal expectations are punished with loneliness, as with Miss Crawford and Maria. Julia’s elopement with Mr Yates comes to be accepted so is then allowed to remain in the grace of her family. 
The seeming acceptance of duty of the lot of women is reiterated, and yet is occasionally undermined as when Fanny refuses to marry Mr Crawford and so goes against the wishes of the patriarchal figure, Sir Thomas. Duty is expected, but so is moral rectitude and Fanny displays the ability to perform both. Morality, however, is depicted as the more dominant virtue.
All except Fanny regard the prospect of her and Mr Crawford marrying as one that would bring her comfort and luxury. His eligible status depends on his background and wealth and she is thought of as foolish to refuse such an offer. Given the way the narrative directs the readers to question these reasons for marriage, it is possible to see that there is an embedded criticism of such match making. This is emphasized when Mr Crawford commits adultery with Maria and so proves Fanny was correct to distrust him. The match between Maria and Mr Rushworth is likewise undermined, and this too is one that was founded on prospects and status.
Wealth and poverty
The acquisition of wealth is largely unquestioned in the circles of Mansfield Park. Money lends itself to the idea of a so-called good match for the likes of Mrs Norris, Lady Bertram and the Bertram sisters initially. Furthermore, Sir Thomas’s interests in the West Indies are barely explored, and we only hear of Fanny asking questions about slavery and are not privy to the responses he gives. 
Edmund and Fanny represent a middle ground as they do not wish to be poor and yet are not overly concerned with material gain.  The news of their marriage in the final chapter is in keeping with the thematic concern of having comfort, but not excessive amounts of it. Tom comes to learn of the mistakes he has made as an over privileged eldest son and Maria is punished as she has behaved as the spoiled eldest sister.
Poverty is barely considered and when Fanny returns to the home of her parents it tends to be a case of proving how the thinness of walls and the smallness of rooms are abhorrent to her alone. The relative lack of wealth is drawn on to show us the slackness of her parents rather than being used to critique the unfairness of the distribution of wealth.