I hate to go "conventional" on you, but there is a reason for the phenomenon you describe: Feminism.
Prior to the birth of Feminism, women knew what they wanted in life. They knew that they could be fulfilled by (a) a faithful, productive, mature husband, and (b) an unpredictable household full of children. EVERYTHING ELSE was secondary. She might have to work outside the home to "make ends meet," but there was never any question in her mind or the minds of their employers what came first: Kids, then husband, then (probably) elderly family members who needed help as they grew older. The Job came last.
The most important "job" in their life was the nurturing of those children, which required management of the household, overseeing the education process, and keeping the husband/father reasonably content.
This is no fantasy; it is the way things were prior to approximately 1970. The cultural turning point was that awful commercial - I don't even remember the product - where the sexy young thang sang that she could "bring home the bacon, and fry it up in a pan," meaning figuratively that she could have IT ALL, career, happy home, and stylish clothes. (Bullshit).
Feminism, as a philosophy of life, declared that women didn't need a husband or kids to be fulfilled. On the contrary, a "modern" woman needed to be fulfilled IN A CAREER, and if she was not fulfilled in a career, she was selling herself short. She didn't need a man or kids or any of that to be happy and successful. In fact, to Feminists, the "housewife" paradigm was nothing but a form of slavery, and a sign of failure as a person.
And of course, today, the more highly educated a woman is, the more she is likely to buy into the Feminism bullshit totally. They don't need no ******* MAN or KIDS to be happy or satisfied or fulfilled. But that leaves a giant hole in their lives. Nurturing is IN THEIR NATURE, and with no kids to nurture, they do crazy shit, like fawning over dogs and/or cats as though they were kids. It is perverse, actually.
So when you meet a young "professional" woman in her 20's or 30's, she is duty-bound by the tenets of Feminism to let you know that she doesn't need you, or any relationship, or certainly any kids to be happy, "...so don't get any crazy ideas."
But the good thing is, Feminism disdains primitive concepts like modesty, chastity, and sexual prudence, so getting laid is not that difficult as long as you are not deformed or overtly crazy.