This is something I realized recently living in New York City where there are a lot of hookups and single women who refuse to settle. Men are biologically less selective when it comes to sex. Women are more selective. With modern hookup culture, frequently you have very attractive men (physically, financially, social status) often hooking up with much less attractive women whether in one night stands or fwb. The other way around RARELY happens. Eg. a girl who is a 9 will rarely sleep with a guy who is a 6.

HOWEVER, when it comes to actual dating and relationships, the attractive men will NOT want to settle with girl who is less attractive. So often, women will meet and hookup with attractive men and BELIEVE that she can actually date him. But most often or not, the guy already knows he will never date the girl. This creates unrealistic expectations with women who believe they can attain that top 10% of men who really just trying to sleep with them.

Brining it back to NYC here, I see a lot of single women hitting their 30s (some of them out of shape, lack good careers) refusing to settle because they all believe they should be able to attain some 6 foot 4 handsome millionaire - especially since they've hooked up with at least one of them in the past. Men fortunately (or unfortunately) don't have unrealistic expectations cuz they never hookup with girls outside their league.