Hang Up time for 2G and 3G networks
So why mobile operators in a hurry to turn off their 2G and in case of some uk operators from 2020, there 3G spectrum, because to allow more airwaves for emergency services and digital tv. Also because 4G and 5G will become the new standard for voice and data.
I personally dont like the turning off 2G as most 3G and 4G coverage is good but in rural areas even 3G signal is hard to obtain. but on a business side, its more productive for them to ensure their sell off old bands and reinvest the money.
Telstra invented the 1st GSM card according to this LinkedIn post