Cutting-edge Germany and the decommissioning of 3G
In Germany, all 3G networks are being decommissioned at light-speed. At the same time, companies like O2 / Telefónica have failed with a widespread rollout of voice-over-LTE, and also, many phones don't support it.
The argument is, that in a few years time we'll have widespread 5G, which will fulfill what was promised (and so far underdelivered) for 4G/LTE years ago.
That leaves you with - again - 2G (!!) for voice in many places, which is decades old, totally insecure and sounds antique.
Beat that.