I am not sure how much TRAI played a role with decreasing the tariffs because they were in the era of no Jio and they were allowing the atrocities of Airtel but Jio came with 4G unlimited data the Airtel fought with TRAI to end the unlimited 4G data by showing a rule then Jio announced plans and now the market is controlled by Jio and Airtel. Even now they are increasing the rates gradually and TRAI can't do anything about it.
This news came out a few days back,
Govt working on proposal to waive a substantial portion of AGR dues: Sources. This will help stop the duopoly of Jio and Airtel in the current telecom market. BSNL 5G will be launched this year a lot of rural users of Jio and Airtel will shift and port their numbers to BSNL because of the network coverage.
I still think Jiocoin is just another marketing strategy by Reliance and will not hold any significant position in the crypto market.