I do not agree with this fact. For sure extra guidance helps a child in better understanding but teaching them isolated from other tuition centres is a wrong method. There are endless tutors available that teaches in the group wherein a child gets in touch with other students also and openly takes part in a group discussion in regards to any subject. It creates a sense of healthy competition among the kids.
There is another side also wherein we can say that private tutors are more focused on one child and will take the child's education for granted.
It is the whole sole responsibility of the parents to keep an eye on child as well as the tutor whether private or outsider.