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.
It's getting worse than ever. I don't see so much lack of B41 as I see unusable B41. -85 B41 signal that's as usable as communicating with Antarctica from Oxford using smoke signals (have to manually defeat B41), dropping calls on handoffs with good CDMA signal, transitions between LTE bands are accompanied by up to 10 seconds of "No Service", similar periods of "No Service" during handoffs between LTE sites even with good signal. I can reproduce that behavior on the devices, and the dropped calls on four.
Still, the only responses I get from Sprint are basically "Get lost" answers.