Why didn’t you marry him you stupid stupid girl?
If I want to go logically wise: Because it wasn’t historically accurate and dear Miss Austen advised her not to marry him.
My fangirl side says: Damn you with being historically accurate, this is a movie and they should have ended together giving the world beautiful curly blond kiddies, while Tom character in this movie was a mix likeable and not likeable they still looked oh so adorable together and she made him feel joy and what not.
I will write a fic I say and they will end together!!!!