Yeah, the game has changed in the past few decades to the point where the rich (Chads) get richer and the poor get poorer, sexually speaking.
FWB situations are fun for Chads, and keep "single women" somewhat satisfied. Under the old, more sensible rules, she "should" just get a boyfriend.
Also, it is not uncommon for people to break up but the woman keeps fucking the ex-boyfriend. She should go back into circulation, but she doesn't.
Lastly, in the past, before 1970 or so, when an unmarried woman got pregnant, they just got married, thus taking that Chad out of circulation. Now, they don't get pregnant, and the woman is a single mom who is either not interested in dating or almost all men are uninterested in dating her, meanwhile the man keeps fucking other women and even getting them pregnant.