Because superhero movies tend to have a solid ROI, which is why they get made: to make already rich dudes even richer. How do you plan to flesh out your seductresses Nazi assassin movie idea other than “she seduces Nazis and assassinates them” and still be a box office hit?

Find or be a good writer, get a decent script, and if you can convince enough movie executives that they’ll make bank off of it, your idea might stand a chance.