We didn't have children living on the streets either. But the reason for that was that giving children up for adoption was essentially illegal, the women of our country being denied contraception, having a mandate to reproduce and raise offsprings. And also foster homes were essentially prisons, some in really poor conditions; at least those that had the children with special needs were absolutely horrible (i.e. the new men couldn't admit the existence of the handicapped).
So you know, the actual reason many of these countries haven't had children on the streets is because the police wouldn't allow it ;-)
And I feel compelled to mention this for those among you that might get romantic ideas about how communism happened to be in practice.