These seductive characters used to be the mainstay of movies. So, where did they go?

Writing in Obit, Kevin Nance says,

In the restless middle of the 20th century, the femme fatale, the dark queen of film noir, jolted the silver screen with an electric sexuality and lethal cunning it had never seen before. She smoldered, she coveted, she hated, she schemed and, above all, she manipulated the men in her life - alternately offering and withholding the promise of love and a mind-blowing screw, playing the poor saps like puppets as the moment required. Along the way, she provided a group of gifted, intrepid Hollywood actresses a chance to shine in a way few of their rivals ever did or could, which is to say darkly.

Anyone who's seen Gilda or Double Indemnity knows what he's talking about: take-charge postwar dames in control of men and their sexuality. Of course, they're not all powerful. As the author points out, they tended to be written by men and there was more than a hint of misogyny at work in this portrayal of black-hearted steeliness. But, at the same time,

The femme fatale isn't passive, waiting for her life to improve on its own. Instead she takes the initiative, attacking the problem with nerve, drive and intelligence. Yes, she uses cat's-paws, rather than her own paws, to accomplish her goals. But whose fingerprints do you want on the smoking gun, yours or someone else's? Yes, she uses her sexual power over a man to get what she wants, but power is power. She is the actor, he the acted upon. It's she who controls her destiny, for better or worse.

Part of the dearth of such characters must come down simply to the end of Noir. But I think part of it is that phenomenon Jennifer Wright identified: self-possessed women are out of fashion. We like our heroines kooky and somewhat incompetent and our villains uncomplicated. We don't much go in for moral ambiguity, period, which pretty much leaves out noir as a genre. And yet, offscreen, femmes fatales fasciante us as much as ever, be it the power behind a corrupt dictator's throne, or the wife of a Ponzi schemer. It's the pictures that got small.

Cherchez La Femme Fatale [Obit]