It's not just the bands. The 6 is capable of VoLTE, but VoLTE isn't available everywhere on every carrier. So it still has to be able to drop down to 1x, whic

It's not just the bands. The 6 is capable of VoLTE, but VoLTE isn't available everywhere on every carrier. So it still has to be able to drop down to 1x, which means CDMA for Verizon, Sprint, and US Cellular, while AT&T and T-Mobile use GSM. You'd think Apple could put out just one model when the 1x networks go away.