Who said school work?
We’re talking about developing a baby into a good kid who will in turn will be a child with ambition and integrity. We’re not talking about a mom MAKING a kid study, we’re talking about a mom who has been there along the way to create a child that understands that there are intrinsic rewards for good behaviour and negative consequences for poor behavior.
A good student doesn’t have to be watched over. 
And why does this have to be all or most of the time? Consistent parenting is good parenting. You cannot create a child that understands rewards and consequences if it isn’t consistent. And daycares cannot provide a seemless, consistent system. There’s a ton more that goes with mother-child bonding. A TON. That’s why you can get your PhD in this…
edit: And what you said is exactly the type of thing a neglective mother says.