When feminism erased the differences between men and women, especially in their societal roles, we forfeited the selective power of desirable women, which makes becoming a desirable man less rewarding and less feasible. We need a factory reset on western culture.
Discussion
It's coming
I think the onus is on beautiful women to revive chastity and modesty.
Other women don't have the "clout" to get away with it, as easily, and as long as men think they can get Miss Lovely for a lark, marriage will continue to decline.
Responsibility is mixed. Those with power are responsible to use it properly, but parents are responsible to educate their children in such a way that those children grow to be responsible when they receive power.