It's not really surprising, is it? In a society that demands of women to get married and raise kids instead of work, it's mostly women who aren't allowed to marry and have kids who get to do things like follow a higher education.
My mom got an engineering degree, '64-'68, and was also pretty much the only woman there. Women were going to college then, it's just that any woman (like my mom) showing engineering aptitude was encouraged to be a teacher since, as she was counseled, "women don't become engineers".
If you were really lucky you were born into a rich family that could exempt you from the role given to you. The church may had been a alternative escape route available for women, but I don't know if that was the case here.
aren’t allowed to marry.
Financial capitalism at its best.
You just have increased financial insecurity because now a family must rely on two incomes. In the past, when one spouse lost their job the other might find one or go to full time employment, now both parents have to be employed to be financially stable. That isn't even progress for those who have to work for a living. For the investor class it's of course different.
What makes you think it was common practice? Exceptions are a thing…
Source: have seen the ads specifying such.