Not sure if you have included 5G.
As the Core Network is now an all IP environment and there is a lot of understanding about QoS / QCI there is now a reduced need for 2G / 3G Circuit Switched solutions, e.g. CSFB, etc..
4G and beyond is now the main “theme”. VoLTE, VioLTE, SMSoLTE, etc.. are now the Services that will use a 4G IP Core Network. 5G will bring about Massive MTC – Machine_Type_Communication – and Industrialised IOT – Internet of Things.
At the time of writing (2019) there is a lot of focus on the deployment of 5G solutions. 2G / 3G vertical assets have been sweated and several CSPs are now winding down the 2G/3G Networks
VBR/ Wallis Dudhnath