If we look at Japan as an example, the observation I would make is how much people interacts with computer that simulates or replaces physical social interactions with a computer facilitated one. Be that a social networks, traditional media, movies, tvs, but also practical every day activities like work, shopping and entertainment. This interferes on a psychological level how people form emotional bonds, which changes behavior in both men and women.

If we observe that women are choosing from a smaller pool of men, one way to describe that would be that women turning into more tournament-like in their strategy for reproduction and away from pair bonding. Tournament and pair bonding strategies have both benefits and drawbacks, and both are related and possible influenced by perceived social status of potential mates.