for her dislike of Elizabeth. I'm sure Caroline thinks that if she had no rival for Darcy's attentions, she couldn't fail to reel him in.
And I think her snobbery arises from having been educated in a fine seminary, probably among girls whose fortunes did not come from trade and who may have looked down on her and Louisa, making them both even more class-conscious. I don't think she'll be a spinster, and even if she were, she has sufficient fortune to ensure that she won't have to be completely dependent on her brother and sister. But I do think she sees Louisa's marriage as a bit loveless, and she fears she too will marry a man of "more fashion than fortune" if she fails to get Darcy. In my imaginings, I see her making a play for Col. Fitzwilliam.