No matter what Stephenie Meyer wants to believe, Austen is much more Married with Children than Twilight. There are a lot of marriages, but not much love to go around. That's because most marriages are based either on economic necessity or on lust—and economic necessity might be a slightly better reason for marrying than lust, but it's still mediocre at best. And the idea that you'd leave your entire family to run off with an impoverished soldier/handsome vegetarian vampire? Pure idiocy. Romantic love is a privilege that most people never earn. And we do mean earn: love is an emotion available only to intelligent, mature adults. It's the crowning achievement of a good character.
Of the entire Bennet family, only Jane and Elizabeth are capable of true romantic love.
Love is a relationship bonus, but it's not entirely necessary. Charlotte is happy because she has low expectations.