Well it's all a mater of perspective, out of which end of the telescope we view a happy marriage. So I propose we reverse the telescope, so to speak, and describe to Jane Austen what progress we have made in 200 years.
Nowadays it is universally accepted that a young woman marries for love. And statistics show that she divorces (50%

after two years. About 20 - 60% that do not marry have children out of wedlock and most do not have the means to support them, the burden falling on society. As for happiness in a marriage I do not have any statistics but it may be instructive to note that Austen does not describe in her novels a felicitous marriage of any duration. I wonder if Jane would view our marriages as progress?
Jane Austen wrote from life and in creating these characters, it is safe to say that she had a fuller view of marriage than most women of her age. Theory not outstanding, it may be instructive to consider that she married badly and there is reasonable evidence that when expecting, took her own life due to dehydration.
As to Charlotte or Elizabeth, they have only the attributes that she wrote of. They exist only in the pages of the book and when the final word is FINIS, so are they.