This costs infinite money.

It's impossible to scale, because nobody wants an environment where their child is not getting attention from compassionate, engaged adults throughout the day. To get the same level of care as a stay at home parent, you need as many care workers as there are families with young children. And if you pay those workers comparably to the average wage, you need to tax the entire wages of one parent in each family to cover the care costs.

It's probably much cheaper to write checks to families encouraging them to have one parent care for their own children full time.