Ira Levin surely dislikes a happy ending.

This story is terrifying, sure, but the way things ended surely leave me in hopelessness. How would, how could, the bright and talented women win when they are surrounded by men who want nothing else but housewives who prioritize their husbands (sex drive included) and house chores above all else, who have petit waists and huge, perky boobs, who reject every social gathering invitations from the other ladies because who the hell need women friends???

My heart breaks for Joanna and all the Stepford wives.
(Stepford) Men are trash™.