That may be true in some cases but I would hazard those cases are <~1% of all rape cases. As a woman, I can tell you it wouldn’t be worth it (time spent, reputation destroyed, being called a slut, whore, etc.) just to tarnish someone’s reputation and try to get any financial compensation (which is incredibly dubious in the first place). Yes, those sinister reasons are deplorable. However, the media shines a special flashlight on women who lie about rape although these cases are fairly rare; the overly-slanderous media attention only serves to perpetuate discrimination and hatred and to scare women (who have legitimate accusations) from ever saying anything.