Lightning had the contact springs in the phone, USB-C has the contact springs on the cable. This is the part that wears out, and USB-C moving to the cable is an improvement.

Throughout its life, Lightning suffered from "black pin plague" where when springs in the port wore out, the power pin would start arcing. Now you have a cable with poor connectivity on the power pin, and you use this cable in another Apple device and it starts arcing on that device as well, causing that device to start transmitting this disease. It was a terrible design and USB-C does not have it.

https://ioshacker.com/iphone/why-the-fourth-pin-on-your-ligh...