In relation to childcare, the simple truth is until very, very recently, only women were entitled to take maternity leave, therefore men would have to quit their job in order to take time off, and that time off would probably be unpaid. Unless the woman earned significantly more than the man, and in most couples I know the difference in income between the two couples pre-DC1 isn't much different, then financially it would make more sense for the woman to take paid maternity leave and look after the children. The vast majority of families won't earn enough to emply a nanny even with both parents working, and most childcare won't take in a baby of a few weeks old.
Also, many women won't be physically recovered enough from their birth within a few weeks to return to work, and they may be breastfeeding and not be able to express, so they physically need to be with their child in order to feed him/her.
It's only so recently that things have changed. But for 99% of the mothers on a site like this, the only option available to them would have been the mother taking maternity leave for at least a few months. And then their career might be interrupted.
I swear, sometimes when I read discussions like this it is as if some people believe men aren't getting pregnant and giving birth out of deliberate choice.
I would love things to change now men can take paternity leave. But it's not straightforward to judge women and their decisions when there really wasn't much choice.