How it used to be
In the past women got married very young mostly virgins. They gave up their most attractive years to one guy in return for commitment, for being taken care of when they got older, for financial security etc.
From todays perspective it might seem weird for some people but it was actually a pretty balanced agreement. In the first few years the womans value might be higher than the guys but as she got older and he became more established in whatever business he was doing things would switch and his value would be higher than hers and it would balance out overall. Of course every case is different but the average marriage would work like this.
Things have changed a lot
Today women want all the benefits of their youth, beauty and fertility for themselves, they wanna party like there's no tomorrow and hook up with the guys that turn them on the most. And they still expect a quality guy to be ready to marry them as soon as they feel like it. They want to max out the benefits of their youth and beauty for themselves and then try and lock a guy down at the very last second before their SMV dips below his.
This might have worked for a minute, us guys don't always catch on to the games women play super quickly but over time guys were like wait a minute.... what am I getting out of this?
It's only bad news for the guy
Not only has she used up her most attractive years riding the cock carousel as it's called, she will be mentally damaged and won't be able to pair bond with the guy she's marrying because she's had so much sex that she doesn't know woman she's supposed to be anymore.
On top of that she will most likely resent the guy that's bailing her out. Women think the hottest guy they've been with is their own level even though that guy never wanted to be with her. When a girl who's a 5 manage to sleep with a dude who's a ten once she'll go through life with the ego thinking she deserves a ten. And when a guy who's a 5 or even a 6 or a 7 comes along and marries her she will hate him for reminding her constantly that she's not young and hot anymore and can't have any guy she wants. Instead of being grateful for him bailing her out she'll resent him for not seeing how worthless she is and feels inside and take it out on him.
In the past guys would be rewarded for committment and marriage even if they weren't the most attractive guy ever they would find a wife who would take care of them sexually and be a homemaker. Nowadays guys have realised there's 0 benefit in committing to a girl anymore not only will she look down on him for not seing through her game she will cheat on him with guys who put in 0 effort and get more out of it than him. So now guys just don't commit anymore at least until they're maybe 65 or 70 but still don't marry her then just date long term. Guys don't even want to date girls in their early 30s anymore because they know they have the baby rabies and the risk of an "accidental" pregnancy and demand of marriage is very high. 27 is the max a lot of guys will go for and it might get even lower as women adjust their strategies.