This happened because:

Female hypergamy is through the roof.

Women's expectations for partners are very unrealistic.

Dating apps like Tinder have helped foster the degeneracy of hookup culture where young women whore it up with Chads then after they hit the wall they try to find a rich beta male to marry.

Society has been heavily favoring women in education and in hiring. There are a lot more well paid college educated women than there are college educated men.

The widespread rise of feminism in western society means there is a pervasive anti-male sentiment in society. Women can easily ruin the lives of any man with a few words of a false sexual allegation.

The witch hunting culture of the metoo movement has caused a lot of men to be rightfully wary of blindly trusting women not to ruin mens' lives.

All of these previous mentioned factors have caused a rise in MGTOW where smart men realize that gambling on women is not worth all the potential risks.

I myself am a MGTOW who doesn't want to date, fuck or cohabitate with a woman and I definitely will never marry.