It requires a third internal antenna and Apple omitted it. Oh well, it's a superior network nationally for both LTE and 3G. Plus, every time I seem to need voice and data simultaneously I just so happen to be on wifi and if works on wifi.
Gotta save something for iPhone 6 maybe.
I think it's because less people talk on phones then text now so talking and surfing is down among the target audience. I was always surprised that the CDMA carriers never came out with a commercial of kids laughing at someone talking on the phone and surfering when they would send links via social networks and things faster.