I think that regulators too have more effective control over the private organisation as they can be penalized heavily and their licence is always at stake.
The management also in such organisations, are more capable and effective and they are more responsible towards the society
Now the concept of 'self-regulation' has come but from Indian experience gained so far I don't think we have yet reached that stage to see the success of this concept.We seldom do the thing unless we are compelled to!