Handcream, your last post sums up to an outsider what has happened.
However, we don't know what goes on in an individual's mind or what their exact circumstances are.
Was she pressurised by family to keep the children? The grandmother reported her to social services for going out and leaving the children alone but was she happy about her grandchildren being in foster care? Would she be worried about not seeing her grandchildren if they were adopted?
It's reported that Rosdeep attempted suicide after she broke up with the twins father. Did she harbour hatred for that man and then look at Mikaeel and project those feelings onto him?
She could have got help at any stage but why she chose not to, we may never know. Pride. Shame at letting her mother and sister down.
I can't imagine telling my family or friends that my children have been taken into care so maybe that's why she kept them but neglected them.
We don't know if the beatings and subsequent death of Mikaeel was the first time she had become violent or whether there were regular beatings to just him or all of them.
Don't forget, they were all returned to her, so there must have been proof to social services that the children were not at risk of any physical injury.
The court case may reveal more but it's possible we may never know.