Likely for size reasons. "Micro" USB is still pretty thick on the iPhone thickness scale.
I'm just speculating, but it seems more reasonable than the "because they can charge you for it!!!" hand-waving going on in my sibling comments.
I'm just speculating, but it seems more reasonable than the "because they can charge you for it!!!" hand-waving going on in my sibling comments.
To be honest, I'm not sure if that alone is really worth the extra annoyance of a new connector.