In my opinion, the root cause of such kidnappings is the void between middle class families. Range of middle class has increased tremendously. Upper range of middle class is fighting to be among the upper class.
On the other hand, poor people are fighting for their survival. Easiest way for them to make money is by illegal means. I am not approving their illegal activities but it is way too difficult for a poor person to survive. You can see exponential rise in the rate of kidnappings in Bihar,UP, & Delhi area.
An ordinary person cannot buy things, they are too expensive. Whereas some other well-off middle-class people don't even think twice in spending money. India's economic growth has been very good for specific class of people but ordinary people like government employees etc. can barely survive. No wonder you see so much of bribery/illegal activities among them.