eCall, alarm systems, elevators and many types of sensors.

2G should die though. You can use the frequencies for 4G/5G to get better reception.

And if the thing depending on 2G has the space for it (like a car or an elevator) then the thing can be upgraded with hardware that supports 4G/5G.

…Unless the manufacturer is a dick and wants you to buy a whole new thing. I suspect that this will happen a lot.