yes, it's like the idea that men should always be taller than women - there's a direct correlation between how much taller the man is, and how much money the movie grosses.
We are taught so much that men will be big, strong protective etc that it's hard NOT to find those features attractive.
So we go for older men, and then we find that it doesn't make financial sense to keep earning once we have children, and so the stereotypes continue.
for those saying that their own friends/experiences are different - statistics say otherwise. women still marry older (if only slightly older) guys, and that means they've had a head start on the career ladder. Also, if it's been a couple that have been together for a while, she may well adapt her career to his even before marriage, by taking a lower paid job that is closer to him & his job, rather than going for the higher paid job, no matter how far away it is.