Marriage is in decline for many reasons, but chiefly because the internet became easily accessible. Suddenly, guys like me were able to read divorce horror stories from men from all 50 states; I was reading them on sosuave 17 years ago. Posters on sosuave linked me to other websites where guys were saying the same thing.
I was born at the beginning of the millennial generation - the people that should be getting married now - and I've had multiple opportunities to get married over the past decade. Never felt up to it. I bet there are many guys from my generation with a similar outlook.
Plenty of guys I grew up with did get married, and some still are. Some are divorced, some are still married. Probably half and half. But that doesn't mean that the ones that are still together won't get divorced in the future.
Maybe it's cognitive dissonance, but I look at the benefits. My money is my own and I have plenty of it. I never spend it on frivolous bullsh1t. I do what I want, when I want. A woman would never allow any of those things in a marriage, or a LTR for the most part.
From my experience, women always want their fair share: of your money, of your time, of your emotional tranquility.
Those are three very important things that every man should think long and hard about before he concedes them.