2G is hard to shut down, because it just works, and many of the core services and old phones rely on it. It will survive 5G, 6G, 7G an other Gs.

2G is being shutdown (or already has) in many countries and those old phones and core services will need to be replaced.

2G also needs a tiny amount of spectrum in contrast to the newer standards, as it was designed almost exclusively for voice calls, where a few Kbps is sufficient for good quality speech. (And 64kbps, which is only 8KB/s, is considered "toll quality".)

4G is becoming the "baseline" and replacing 2G in many of those services, especially the "low energy" IoT implementations of LTE.