Louisa May Foster (Shirley MacLaine) is pushed by her mother to marry the rich Dean Martin for money, but she marries Dick Van Dyke for love. There is a silent film parody where they deal with their poverty by saying that Love Conquers All. Dick Van Dyke then finds success at business and bankrupts Dean Martin out of spite, but then Dick Van Dyke dies of a heart attack from working too hard.
Shirley travels to Paris where she meets an artist played by Paul Newman. There is a French New Wave film parody featuring 9 scenes in smaller and smaller bathtubs.
Paul Newman then finds success at art, using a music powered art painting machine (the sound palette) but ultimately the machines beat him to death.
Shirley then meets Robert Mitchum who is already rich. There is a big budget film parody about "love and what she will wear next" featuring 17 costume changes in five minutes. Robert Mitchum resolves for them to have a simple life on the farm but he dies in a milking accident. Never milk a bull!
Shirley then meets Gene Kelly, a struggling song and dance man who performs in clown makeup. There is a big musical parody featuring singing and dancing on a boat. Pushed for time one day, Gene Kelly performs without makeup and finds success, but is trampled by his legion of crazed fans.
Finally Shirley MacLaine meets a humbler Dean Martin, marries him and finally finds love.
Thanks Don P!