I thimk this idea that if it is established that it is the 'best' for children then we should provide it as parents, goes back to the OP's idea of scrifice.
Why cannot it be admitted that many mothers love thier children but some sacrifices are too far, and they will seattle for good enough parenting.
For some mothers thier job is a scarifice they are not preaped to/cannot feel they can make. They don't abondon thier children, they make good enough, if not ideal arrangements and live with that.
There is an assumption that we should all want to provide the absolute best and make any personal scarifive to get that.
In reality mothers have thier own needs/issues to deal with and will make compromisese that they can live with. This in true in amny araes not just work.
When did motherhood become this aspiration to perefction? and binvolve eating youeslf up if you didn't meet your childs emotional needs entirely and consistently.
Read 'The Mommy Myth', it is being bouht into Big Time, I see it all over MN.
Mothers are just people. Good, bad, selfless, selfish, and a mixture of each at different points in thier life.
Stop beatinh youeslves ,and each other, up.