MFi is a non-starter. The amount of revenue gained from that program is literally inconsequential.

Another possibility would be for Apple to simply bump Lightning speeds.

And actually, if Apple bumps the camera past 40MP and enabled 8K video, then I think that they would almost have to switch to USB-C/Thunderbolt on the iPhone Pro.

Can you imagine having to extract a large 8K video over USB-2.0 speeds?