"I think there are differences, possibly for biological reasons, between the sacrifices mothers and fathers are prepared to make, ime as a rule men won't put their DC consistently above their own needs for a sustained period of time. Mothers usually do."
I've noticed this, although I don't think it's universal for men. I do think there is also an argument to be made that, for many men who invest a lot of their effort into their careers, they see it as something they are doing partly for their kids: to give their kids financial security and a nice home etc. But sacrifices that a man is making for his career, even if he is in a career that is difficult for him or that he dislikes, also come with significant benefits that accrue directly to that man: his career progression, his pension, etc. When a woman makes sacrifices of her career for the benefit of her children, then if the marriage breaks up, the benefit she gets is her good relationship with her children (but not always; some mums sacrifice a lot for their kids and yet still have a bad relationship with one or more of their kids). It's great if she has a good relationship with her kids, but that's not the crux of why she sacrificed (usually she did it because it was necessary for their wellbeing, not just because she wanted them to like her), nor does it put food on the table and a roof over her head. It's a valuable benefit in a spiritual sense, but doesn't meet her needs in any practical sense.
It's also not always true that women put the children's needs above her own, but I think there is much more societal pressure for women to do so, and it seems to me mostly when the kids are not living with their mother, there's usually mental illness or addiction or something like that in the mix.
But in the main, I do agree with you. And I think one problem with structuring society so that women have to self-protect from men's tendency to do this, is that it puts the woman in a dilemma between her child's survival and her own. If your child is sick, but you need to go to work, do you take your child to the doctor or do you go to work? If you might get fired if you don't go to work, then you are highly motivated to just look the other way on your child's illness, and that is a risk for your child.