The Gift to Consumers : The Tariff War

From MTS to TATA to Aircel to.....all are following the same trend....retention with offers that a few months back was unimaginable...
How will they sustain in terms of Revenue....can anyone explain on the calculation based on which Companies devise these plans to woo.

The transition from ARPU to " Pay per Sec" and finally to "Pay per Call"....where will it lead to. And all these are happening only for New Carriers be it GSM or CDMA and for players who are in the Roll out phase for their pan India presence. But looking at the Market leaders 2 players have not responded yet and they are maintaining a bigger share in the Revenue part.....

So how long will it continue and where will it ultimately lead to !!!!!!!!!!!!