I think the sexual revolution has solved some problems. Making life easier on those that didn't follow the social norms. But the societal changes over the last century have also created new problems that once again put us at odds with our own biology.
I think the "someday" part is what is screwed up now. Modern Society says to wait until you are economically independent and stable in order to start a family, which basically means 80% or 90% of the population would have to wait until their 30s to get married and have kids and thus under the traditional model that is when they would start having sex. Maybe under current conditions society would just tell most people that they shouldn't get married or have children at all.
But our bodies are built to start having sex when we are teenagers. It is also a biological fact that we should be having children as teenagers and in our 20s.
Having children in our late 30s and early 40s just doesn't make as much sense biologically. And socially you are running into the biological wall of old age when parents are as old as grandparents used to be and grandparents are too old to help raise the children. Instead we are being forced to rely more and more on complex economic and social arrangements to help care for our children. Arrangements which may or may not be economically sustainable or socially desirable. We are living through a patchwork of social experiments, some of which seemed based on the desire of an elite to further their own societal dominance.
So, the tension we have now is a direct result of the social engineering that has gone on to promote getting married later in life versus the traditional family structure (admittedly also socially engineered) which only satisfies the sexual urges of young adults if they are allowed to get married at a younger age.
Sure getting married young and having children causes its own social problems if those marriages fall apart. But so does having children outside of marriage and never getting married.
I don't think there is an easy answer that will get everyone a life long spouse early in life and put everyone on the path to create strong families. But neither should their be an easy scapegoat either in modern or traditional values.