Before Jio's IUC change, they were providing truly unlimited calling, whereas Airtel Vodafone and Idea aka AVoId gave a soft limit of 250 minutes a day, and 1000 minutes a week. No one complained of that. The complaints only started now, because they can see that they're paying extra for IUC minutes.
Airtel is still trying hard to get back to 250 - 300 ARPU, and wants the IUC to stay. They even wanted to raise it back to 14p/m so that they can continue their daylight robbery in hiking the plans. They know that only Jio is the only one who isn't benefited because of the traffic imbalance.
Bharti Airtel has urged the telecom regulator to postpone the scrapping of interconnection usage charges by at least three years from the planned January 2020 deadline, saying traffic symmetry between networks has not been achieved and over 400 million mobile users continue to use 2G networks...
telecom.economictimes.indiatimes.com
Believe it or not, if TRAI scraps IUC on 1st Jan 2020, the cartel will rush to close down 2G, and it will be complete by 2021. If not, they'll close it in 2030.