We are predicting IPhone will change to the USB-C when the device is going to support 30W charging like the IPad Pro.
Apple has already adopted USB-C for the IPads using 30W max. charging, but the IPhone 12 is still using their proprietary Lightning Connector with 20W max. charging.
Apple Insider speculated that Apple is unlikely to migrate to USB-C and Touch ID anytime soon, firstly due to profitability and another is due to technical reason. It was mentioned that the USB-C waterproof specification is lower than Lightning Connector and Magsafe.
“Therefore, if the iPhone abandons Lightning in the future, it may directly adopt the portless design with MagSafe support instead of using a USB-C port.” – Ming Chi Kuo, Apple Insider.
This will depend on whether MagSafe or any wireless charging can support up to 25W or higher in future.
Currently, Samsung has their own Super charging speed for 25W, but Apple is still trying to catch up.
According to MacRumors, IPhone 13 is rumoured to have 25W fast charging, which is an upgrade from IPhone 12 which is currently maximum 20W (9V x 2.2A) charging. However, it does not say if 25W will mean the IPhone 13 will need to change the lightning connector to USB-C.
So if IPhone 13 is upgrading to 25W and is still using the Lightning Connector, this means that the Lightning Connector has a maximum wattage of 25W. Currently, Apple does not have any 25W USB-C charger in its lineup, so if this suddenly appears in the Apple store then we know its coming.
We may need to wait for IPhone 14 or 15 to get 30W charging, which may then require the USB-C to replace the lightning connector. Then finally we will only need one USB-C cable for all devices.