Lol so people travel in 3 AC just to enjoy a difference of 3-4 degrees? If every thing is regulated and controlled and subsidized in the country, it will be in tatters in a few decades. Those who can afford 3 AC will pay and travel. Those who can afford 2AC will travel in that class, those who cant travel in these will travel in sleeper and those who cant travel in sleeper will squeeze himself in general.
According to your logic, I will travel in 3AC but I want cheap tariffs there also. Suggest you to read some basic economics sir.