My dad's GS5 won't see B41 lots of places. My mom's GS7 acts like my Nexus 6 and 6P, and so does my brother's Motorola X4. The Nexus 6 and X4 seem more apt to drop B41 if not getting any data through it. Maybe the RIL is smarter. Even when I do have unusable B41, SMS and MMS do work over it.
Incidentally, I propped my phone up on my car dashboard (recording) for a minute on my drive home home earlier today in order to show somebody how bad the rain was.
The resulting video (68 MB) took over 20 minutes to upload 23 MB of over B41in Waterford, only to fly through the rest in less than a minute as soon as it jumped to B25.
Not as quickly as you think. China Telecom for example still has 250 million customers on their CDMA/LTE network. China won't be phasing out their 2G networks anytime soon, their 3G networks will go first (W-CDMA and especially TD-SCDMA). CDMA's 3G and 2G are compatible standards so will maintain that as well. Between them and Sprint, CDMA will survive, but it will be niche.