So Hera vs. "Evil Devouring Mother"

First let's take a look at the case of Snow White.
She's the daughter of a royal couple, her mom dies, and her father takes another (young?) women as wife. She gets jealous and wants Snow White killed. The rest of the story isn't much interesting in our case.
The same thing happens in Cinderella to some extent. Her mother dies, her father marries again and her step-mom shits on her on every occasion she gets. No murder attempt this time, but she suffers.
To me it's quite clear that in both cases the step-mom, the new wife considers the heroin a competition. She is a reminder of the late wife - whom possible the pater familias very much loved. She is also viewed by the new wife as a distraction for her husband, who has to divide his attention between the new wife and the daughter.
I'm reading in Wikipee that in some version of Snow White, no new wife appears, but the actual mother is the one who gets jealous of her and wants to get rid of her.