How come we never got a film adaptation of BD Hyman's "My Mother's Keeper"?

Even Brooke Hayward's snoozefest of a book got a TV movie adaptation with Lee Remick.

The book itself would have been hard to adapt since it's essentially BD complaining and whining over how awful her mother was but her examples usually seem so mild. At worst, Bette cursed a lot and was mean to her sister.