This is a result of the feminist movement, pure and simple. Back in the 60s and 70s, when this first got promoted as "women's lib", the idea was to free women from the drudgery of being housewives and mothers, plus a rise in equal pay, opportunities, etc., if they chose to follow a career. However, by the early 1980s, the radical anti-male element of the movement had taken control of it, producing such nonsense as "a woman needs a man like a fish needs a bicycle", and "anything a man can do, a woman can do better". That, of course, was nonsense, but it was swallowed hook, line, and sinker by an entire generation of young women.
Men didn't do much better, being reluctant to relinquish the reins of their "old boy" networks, and many of those who had positions of power in various companies and institutions decided to put these upstart females in their place, and the result was a series of sexual abuse scandals perpetrated by corporate bigwigs, entertainment personalities, and politicians. Once the news of this hit the airwaves, hundreds of women started coming forward with tales of everything from unwanted looks from men to outright rape by male bosses, co-workers, teachers, etc. Not all of these may have been true; but enough of them were to result in a backlash in the form of the "me too" movement.
The problem here became that a lot of women who felt marginalized or discriminated against by the males in their orbit decided to "get even", and launched sexual harassment actions against said men, even when the "harassment" might have consisted of nothing more than a friendly smile as the guy walked past her. And, the HR offices and courts usually (almost invariably) sided with the woman, because "everybody knows that a woman can't instigate or commit sexual harassment".
In the end, a lot of guys who were, if not totally innocent of actual abuse, were at least not deserving of the cashiering they ended up with; they lost jobs, wives, children, position, etc., etc., etc., all because of the publicized accusations, regardless of whether the accusations were proven true or not. Women in the workplace developed a hostile, "back off" attitude towards men they had to share an office with every day; and after the results of some of the high-profile cases that caused some decent men to dramatically crash and burn, men took the advice, and "backed off". Men would refuse to enter into committees with female co-workers. They refused to mentor them on projects. They refused to eat in breakrooms with them. They refused to enter elevators alone with them. They absolutely, under NO circumstances, would put themselves into any situation where they had to be alone in a room with a female co-worker; the risks of innocuously saying the wrong thing and getting slammed with a punitive damage way out of proportion to the offence committed were just too great.
If a woman was promoted to an executive or supervisory position over men, some men would refuse to enter the office of the woman, even if it meant getting fired. If a woman became their boss, a lot of men simply resigned and left companies, losses be damned. This left women pretty much on their own inside many workplaces, and when situations arose where a man's expertise was needed and was not given, projects and productivity suffered because of it.
Related to the "me too" movement was the treatment men received in divorce settlements. The attitude of the courts to support the woman and punish the man (because "everybody knows that a woman is always the victim in any domestic dispute") meant that a marriage that went sour and ended in divorce resulted in the man losing not only his wife, but access to his children, 90% of his personal belongings, and reduced to a state of literal indentured servitude due to alimony and child support payments that would go on for decades, even if the woman re-married and didn't need them any more. And there were cases where some poor schlub had a wife whom he worked night and day to provide for, she got bored, started playing around on him, and when he found out about it, she started divorce proceedings----all of which might come out in court, but the judge on the bench (who were, many times, female) would simply decide that the man was still at fault because he must have somehow driven his wife to infidelity, whether he had or not.
The ultimate fallout of all this was the so-called "MGTOW" movement, or Men Going Their Own Way. What this meant was, many men not only refused to get married, they refused to have anything to do with women altogether; they would not date, they would not seek relationships, they wouldn't associate with women in any way. And just as "women's lib" was co-opted by the more rabid, anti-male elements in the movement, MGTOW was likewise co-opted by the more rabid, anti-female men involved with the movement. Online forums were filled with men venting about the emotional draining that dating caused, about how marriage is a trap to be avoided at all costs if you wanted to keep your possessions and income, and some of them even equated women to dangerous venomous snakes: be aware of them, but don't go near them. "The juice is not worth the squeeze" is the comment often heard. Men simply opted to remain single, many of them forever. Many married as young men, ended up divorced, and vowed to never get married again. Many might dabble in dating, but when it appeared to be getting serious, they evaporated, leaving the woman confused, angry, and sad.
All of which brings us to where we are today: in the wake of 3rd-wave feminism and the "me too" movement and the resulting backlash with the "MGTOW" movement among men, dating is exquisitely difficult, if not impossible, and marriage is rapidly becoming nearly obsolete. People are still getting married, of course; but marriage rates in the United States is at the lowest level in history; nearly 65% of people between the ages of 18 and 40 are unmarried, and of the ones who are, fully 50% of those, end in divorce. Dating is costly and stress-inducing, and for many young people, marriage and the cost of obtaining a house and raising numerous children is simply financially impossible---a mortgage and 2.5 children is just too darned expensive in today's economic world.
Plus, the residue of the "movements" has left a bad taste in the mouths of a lot of young people, resulting in the sexes warily regarding each other across a gulf of apprehension, distrust, and suspicion. Women have told men "No means no! Leave us alone, you creeps!" for so long, that men have agreed, and they won't approach women any more. Women who do want relationships are frustrated, because men show no interest in even casual dating, let alone marriage. Men may long for a female life partner, but they have simply seen too many hopeful unions smash against the rocks and sink into stormy seas to risk the chance. So, everybody sits where they are, static, separated, and segregated. Marriage rates continue to plummet, birth rates continue to plummet, and the only place marriage and family are thriving is in Muslim countries or sub-Saharan Christian Africa. In the developed and Western worlds, "sexlessness" continues to rise.