Consider that perhaps they NEED to be, in order to keep women from following their urges to chase the "bad boy alpha male". At least marriage was more stable then.
Consider the black family. Is the average poor black child's family life better now then it was in the 1950's, before Uncle Sugar made it unnecessary for mothers to be married to the fathers of their kids?
You know, Papa, I’ve always thought you were a real jerk. Now you’ve proved it.
It used to be that new cars were more affordable. Then government regulations increased the price of cars. Now people see used cars with an inflation-adjusted asking price comparable to what new cars cost a generation ago. Rather than saddling themselves with a used, high-mileage model with unknown issues and no warranty, more men say "to hell with it, I'm going to just use Uber".
Back when people married earlier, a man was more likely to be able to acquire a young wife who would have more incentives to keep the marriage going. The current divorce environment means that the man's price of getting married (when the risk and cost of divorce is factored in) has gone up. Meanwhile, more women spend their prime attractive years chasing after charming desirable men who are only willing to show interest in them if they offer no-strings sex, and then the women have the expectation that some shlub will marry them after they are older and much less able to attract interest from the desirable men.
It used to be that the moral culture kept a lid on this. That is no longer the case.