In "easy" times both sexes just sit around psychologically analyzing each other and thinking about what would be a "perfect" match, etc.

Perhaps in times of serious economic strain and war -- that's when all the BS goes out the window and the sexes come together. Sure it doesn't change the nature of either long term, but it does suppress those natures when more important life threatening issues are on the table.

For example, if we were in the midst of something longer term and worse than the great depression or years into a gridlocked WWIII, I bet dating/marriage dynamics would drastically change.

Perhaps that's a reason why things were different 80-200+ years ago. The world wasn't as comfy of a place...world wars, civil war, revolution, much more gritty day to day life. In the comfort of today's modern world, women don't really need men so they can just casually window shop.

is that your excuse for today?

excuse? I'm just explaining why humans have so much time to think about relationships/sex -- survival has basically been put on easy mode.