A lot of people really don't need the extra space from an SD card, and LTE is just a more costly option with slightly higher speeds. The lack of a removable battery is somewhat of a let down, but be honest, when is the last time you replaced your phone's battery? I never have. People also seem to indicate that you can still replace the battery by removing a few screws, it is just a little more difficult.
I think the US market is moving towards prepaid, non-contract plans, and this is the PERFECT phone for it. On top of that, most of the rest of the world uses prepaid phone plans, which this is perfect for.