2G (GSM, not USA CDMA)
The GSM voice calls don't suffer cell breathing. The 3G was a retrograde design, really giving more speed because of 5MHz vs GSM 2G 0.2MHz "channels", CDMA (based on USA 2G) was a bad idea as the capacity falls to about 50% as it's loaded. The 4G speed increase needs 20MHz channels, though doesn't suffer the CDMA ills on downlink. However 4G efficiency for voice is terrible as it's only VOIP, no native RF voice codec like GSM 2G and 3G has.
The High Street and eBay still sell GSM only watch gadgets and phones. There ought to be 2 years retail notice of turning off 2G/GSM or 3G (SOGA) after ceasing sales. Irish operations only have to notify Comreg and give 6 months notice. Three Ireland acquired O2 Ireland (and thus masts for Tesco Ireland) which has GSM.
This is really comparing MOBILE with real broadband via Fixed Wireless (a rare thing). It's about 12 years old and done before 4G was rolled out. The 3G & 4G issues are true though.
I found last year some phones in Carphone Warehouse were GSM only. Their excuse was that they were only "feature phones" not smart phones.
By all means stop selling 3G (and GSM) phones. A good idea as long as the 4G models work all over Europe on 3G & GSM.