This is a fact that Austen herself most certainly appreciated as an unmarried female of the same social set she was writing about, which explains the centrality of this concept to so many of her novels. Persuasion is far from the only Austen novel where conflicts between emotional love and the necessary practical considerations of marriage arise, nor the only one where ironic changes in circumstance lead to the formation and/or solidification -- as well as the dissolution -- of friendships. Similar circumstances occur in Emma and Pride and Prejudice, for example, and Anne Elliott could certainly have taught Emma Wodehouse and Elizabeth Bennett something about love and politics as these two heroines of these respective novels also navigate the waters of their social class and end up finding themselves husbands, whether or not they even knew they were looking. Elizabeth Bennett regarded most men with disdain -- most people, as a matter of fact -- and was especially dismissive of the idea of marrying someone just for the social connections and/or wealth he could provide. Her mother continually pressures her to accept various proposals of marriage to secure a rise in her station and future wealth and security, but Elizabeth is determined to live her own life and make her own decisions as much as possible. Anne learns, through her misguided rejection of Captain Wentworth and her friendship to Mrs. Smith, that such self-determination is essential both to happiness and to achieving the type of secure future being sought. Where she could really help Elizabeth, however, is in not letting the practical concerns of her social station and family members get in the way of finding love. Though this could not be the primary goal of most position will not allow her to marry someone of adequate wealth and class, Emma cannot find a husband for Harriett among the men of her class because Harriett's social position is under severe scrutiny. Emma even talks Harriet out of marrying a farmer -- a respectable member of the lower middle class -- because she feels Harriett is above him. Anne learned her lesson about such judgments early on in her rejection of Wentworth, and her friendship with Mrs. Smith certainly showed that practically any marriage was better than none for a woman who simply could not support herself in a certain strata of society. Emma eventually earns this lesson, and Harriett quite happily marries her farmer Mr. Martin, but not before a lot of needless suffering.
Of course, it is this needless suffering that supplies the plot for Austen's novels. Emma didn't realize that she was in love with Mr. Knightley when she tried to set him up with Harriett; his rejection of Harriett based on class allowed for his acceptance of Emma (and hers of him, eventually). This forms the primary conflict of the novel. In Pride and Prejudice, Elizabeth's willfulness at first drives away Darcy, then draws him to her. In each of these novels, solutions are ironically found in the very roots of the problems that created them. This almost always involves attempted movements in class, and unexpected reversals of fortune and insight.