This happens because girls are hard-coded (EPROM stuff) to generate desire; this compulsion is established and permanent by age 12. They wish to be desired, Bob from the car wash desires her and he’s not too fat, we’ve got something to work with here. Not being desired is a kind of death.
To be a little less glib, if we look at cinematic heroes and heroines, it’s quite socially acceptable to be a lonely, singular man — and he is often very attractive. It is not popularly accepted to be the same, as female. There are no movies where a woman says, “Get off my lawn.”
Yes, it can be useful to young women to be desired. It is how they obtain resources for their future children. an important goal indeed.
It would seem that many women didn’t get the memo, that it can stop when they get a husband, or when they are of the age when kids are not forthcoming.
I suppose that the feeling of being desired is intoxicating and all; and chasing after it can become a driving force in their lives. But women of old had other tasks on their plate, with little time for engaging in this when it was not needed any more. It would seem that the ability for modern women to pursue this when and as she sees fit would be a luxury good.
Short Answer — It is odd to a fella to see women building their life around this from teen to senior citizen.