The argument of the proponents of public schools, I am assuming, is: the voting power is with the poor since India is largely a poor nation.
That may or may not be true — but this post does not address that assumption.
 — If that argument has not been put forward already, assume I am doing it. And also, I argue, that may work because there are two layers: the rich will demand services and will know how to pull levers; the poor will have the power of vote. In theory, that sounds alright. In practice, it may not work for practical reasons such as how the rich and poor live in terms of neighborhoods — but that is a different story and I assume people who put forward this idea are true bleeding heart types who want to live in a slum to prove a point.