The classical explanation for this is that men are attracted to fertility while women are attracted to status.
I really doubt any self respecting 30 year old woman with a great job is going to find, say, a highschool jock attractive. The appearance of being with someone like that does not do her brand any favors in her social context. She's out of his league.
This is probably a little (a lot) reductionist but it provides a pretty satisfying explanation, at least to me.
Human beings are nasty machines.