“Why doesn’t Apple just get rid of Lightning and use USB-C on their iPhones!” This is why. Ignoring the momentum Lightning had from being a few years older, this is a great reason not to switch. Sadly I know this has become a big problem for people on the new Macs. Plug a USB-C hub in? Now that port doesn’t do Thunderbolt or Display Port. How do you know that? Trial and error. Very un-Appley.
In my experience the connector from Apple is far more reliable than USB C. USB C is a rounded flat rectangle with a piece of plastic in the center and pins between, which is small and can easily be damaged. Lightning on the other hand is a solid metal connector with the pins/contacts on the outside, which is much more sturdier. Lighting also does a nice "click" when connected.
At the same time my nearly 4 year old Samsung Galaxy is holding strong without any wiggle room on the USB port.