traditionally picking up the slack would mean for the man to go earn more money. but women want to keep working. and, this is part of the issue, in middle to lower income families they have to. we have created a situation where a single income is no longer enough to support a family. the economic change is not financial freedom for women as much as a financial dependency on both parents working.
and the narrative we are creating and that we seem to want is that men help in the household and with childcare. and that too is happening but only just enough so that everyone supporting that narrative can point to an example, but not as much as everyone thinks. even in households where both parents are working, most of the housework is still done by women.
Second, you can have “moral equality” without assuming “fungibility.” My cousin just got married. The wife is brilliant—she’s civil engineer. The aunties are all impressed. But if they have a baby and her priorities shift and she decides she wants to stay home (which happens to many women!) those same aunties will 100% expect my cousin to take up the slack and support the family, because he’s the man. Morally equal, but not fungible.