Switching to USB-C on the iPhone would have been a hugely shitty decision given their ultimate goal is clearly to build a phone without any ports at all within a few years.
Consider what would happen in that case: right now there are hundreds of millions of iPhone accessories out there that rely on the Lightning port - everything from headphones to cars to health devices and more. If Apple removed the Lightning port all of those accessories would become obsolete overnight and people would be up in arms about it (just look at the removal of the headphone jack and the storm in a teacup that became.) Manufacturers would bring out USB-C accessories for the iPhone, people would buy them to replace their Lightning accessories, the furore would die down and things would go back to normal, and then boom - Apple removes the USB-C port too.
In the space of a few years they'd have fucked over hundreds of millions of people who wasted money on replacing their accessories and the outrage would be overwhelming. People would be accusing Apple of doing it on purpose just to sell more accessories (which is what they're accusing Apple of right now because of the aforementioned removal of the headphone jack) when in reality Apple has been telegraphing the transition to wireless for a while now.
I don't think this is going to happen any time remotely soon, even if apple wants it to.
Going completely wireless would also destroy the current accessories market. No dongle or converter to fix it either.
Also apple already did change the connector for the iPhone once.
The iPhone will go USB-C because the rest of their products have. They can stay dumb and alienate their consumers, or finally start integrating with the world.
Consider what would happen in that case: right now there are hundreds of millions of iPhone accessories out there that rely on the Lightning port - everything from headphones to cars to health devices and more. If Apple removed the Lightning port all of those accessories would become obsolete overnight and people would be up in arms about it (just look at the removal of the headphone jack and the storm in a teacup that became.) Manufacturers would bring out USB-C accessories for the iPhone, people would buy them to replace their Lightning accessories, the furore would die down and things would go back to normal, and then boom - Apple removes the USB-C port too.
In the space of a few years they'd have fucked over hundreds of millions of people who wasted money on replacing their accessories and the outrage would be overwhelming. People would be accusing Apple of doing it on purpose just to sell more accessories (which is what they're accusing Apple of right now because of the aforementioned removal of the headphone jack) when in reality Apple has been telegraphing the transition to wireless for a while now.