I too am not big on 100 years prediction but as you said it's not unreasonable to expect.

Definitely, India needs to deregulate and I'm glad to see that positive progress is being made towards it in recent times. W lot has been changed under Modi's regime, a lot however still need to be done. You can see India is becoming favourite place of global giants and this has everything to do with India's changed attitude.

You're definitely right about India's advantage to be in the proximity of world's largest population. China isn't very far either. The market for consumption is already there and with government's better for all policies, the projection of India becoming third largest may even complete before 2030. We can also consider the troubles of Germany and Japan which are just higher to India sitting on 5th place.