In the US, GSM (ie 1G and 2G) are already more or less gone; 3G (UMTS) is in the midst of the shutdown process.

In the EU, however, it looks like Vodafone intends to provide 2G through at least 2025.

https://www.multitech.com/documents/publications/marketing-g...

2G is already turned off in Australia and being phased out elsewhere (they need the spectrum for 5G and 6G). 3G is the minimum available.

2g is basically disabled in the US. Go out in the country, signal will be atrocious. Anything outside of a metro seems to require walkie talkies now. I've tried att, vz, tmobile, and sprint, but there's a nice spot I liked to go fishing where I could make phone calls up until ~2008 or so. Traveling around recently I've noticed this anytime I was in an area that had <5000 population.