"Frustrating as it may be, understanding the reasoning behind Apple’s strategy here is simple: computers — a class of device that now includes the iPad Pro — get full-fledged USB-C ports with the accessory ecosystem to match. Mobile products, like the iPod Touch, AirPods, and the iPhone, get Lightning ports, where Apple can take advantage of the iron-fisted control that its MFi licensing program has over what you can and can’t plug in, along with the extra licensing profits to go with it. (There is an argument that Apple prefers Lightning due to the physically smaller port size. But if nearly every other smartphone company has figured out how to incorporate the port on comparably sized devices, I’m pretty sure Apple’s design team can do it, too.)

Would it be convenient for Apple to open up future iPhones with USB-C? Obviously. But it would come at a huge cost to Apple, both in money and control over its most important device — neither of which Apple will relinquish easily. The iPhone is simply too critical to Apple’s core business to risk the chaos of USB-C. It’s not acceptable to the company that someone would ever buy a pair of headphones or a charger and have it not work with their iPhone because the cable is bad or the wattage is too low or specs are not right.

The iPad, on the other hand, lets Apple be a little more experimental and open. It may still run iOS and be subject to the limits of the walled-off App Store, but USB-C adds a new avenue where hardware and software developers can expand what’s possible. Apple is pitching the iPad as a computer, and USB-C gives it a universal, open hardware port (if not totally free of Apple’s control) for the kinds of professional tools that people have come to expect from computers. The added complexity of USB-C may drive people away from iPhones, but it could be a boon for the iPad to entice more power users to make the jump."