Many women view their careers as something to do until they get married, so they don’t make it central to their lives.
This is 2020. Not 1960
How many women under 60 do You know who do not have jobs?
I am sure that the “gap” used to be a simple recognition of human existence - women get pregnant and raise children. The household should continue with most of its pay, and the employer gains nothing investing in a woman who will leave.
Whether idiots want to understand it, or not, men and women are as alike as your right and left hands. They are mostly the same, but God, or nature if you prefer, is not wasteful and they complement each other for the greater good.
Statistics can also be a field of weasels. Some women are more like men and some men are more like women. The outliers get paid accordingly.
I viewed my career as a career. I was paid fairly. I worked they paid. I never checked anyone else’s pay stub. That is rude and fruitless.