"Juuule, imho it is because there is still a not insignificant gender pay gap -- men - not always, but often - tend to take home more money, and so it stands to reason they should continue to work."
The same article also says that female Junior Managers now earn more than their male equivalents, and it's probably more that younger pool of workers who are the ones who will be taking time off to have a family. So it's really not just about who earns more and if you focus on that you're missing the things that we really could do to level the playing field.
I've seen this several times in my circle of friends, couples will be doing similar jobs and earning similar amounts. The decision isn't about which salary is easiest to loose but which person has the best options for taking leave. And on that front the system is totally sexist and presumes that the woman will do it.
Even now a man is only allowed to take 26 weeks and have the ability to return to their position, a woman gets 52 weeks. So faced with the decision as to whether to have one parent at home for 6 months or one at home for a year which way do you think most couples will go?
And for children born before those changes when the man could only take two weeks is it any wonder that it's the woman who takes the break. She was, and still is, the only one really given the chance to do so.
Stop the system presuming that women will be the carers, stop assigning parental rights based upon a persons gender and allow parents to choose what is right for them (most of us aren't stupid you know).
Once men and women have equal rights about taking a career break then you'll see more men take the leave, especially as those figures point out that younger women are now often earning more than younger men.
And then once men and women begin to take career breaks pretty evenly you'll probably also see the gender pay gap at older ages decline as it stops pretty much always being the woman who will be affected by that career gap.