Childcare services - nationalise or corporatise?

In the last week there has been quite a shock-wave sent throughout Australia as the largest "supplier" of Child Care Services (to the best of my knowledge) has gone into receivership.

This has left me to ponder - 'Why is it that a service that is so vital to the everyday functioning of Australia, been provided by the Private Sector?'
It stands to reason that businesses come and go, they rise and fall continuously. So if there is a service that is almost critical to Australia's operations, should it not be 'nationalised' and therefore the continuation of the service is guaranteed while it is still a critical function to the Australian people.

This then led me to ponder - 'what is the criteria for which services are Nationalised and which are safe enough to be market driven?'
Why is it that we have the state or federal Government providing such services as Education, Health, Law Enforcement and rescue services. What makes these services so critical that we are willing to pay taxes for them?

I'm yet to come up with an answer to that - but I am keen to hear other's thoughts.

Alan