I suspect some of it is the changing attitudes of society towards sex. When sex was looked at as purely evil and predatory the “borderline sexual” Dracula was portrayed as forceful, predatory and unsexy. A seductive Dracula was off the table since that would require that seduction might actually work, and admitting that women are sexual beings with agency of their own was unacceptable.
As society became somewhat less categorically hostile towards sex, especially female sexuality, vampires started to slide more towards the seductive archetype; especially as it became more acceptable to admit that women are actually interested in sex and the vampire wouldn’t necessarily have to force her into anything.