This doesn't add up. In a world with Lightning for iphones and USB C for everything else there's a smaller chance of having the correct cable than in a world with USB C for iphones and everything else. Enforce a standard and the problem goes away.
Just yesterday I had to connect my phone to a friend's USB connector in his car but couldn't because the only cable available were the freak that is one standard in one end and another in the other (IE. a standard iPhone cable with USB -> lightning).
Everyone in the iPhone ecosystem already has lightning cable. That is 1 billion iPhone user with at least one lightning cable if not more.
By enforcing a USB-C standard, you are throwing away one billion lightning cable. And as shown in your example, he has one. It works for him, it just happens not to work for non-Apple users. Which isn't a problem for Apple users. What is there to be gain for the current one billion iPhone user, 200M iPad user which are still on lightning ? I have room full of lightning cables and devices that use it, but zero USB-C devices.
Arguably switching to Wireless ( MagSafe ) made sense from a UX perspective. Although I question whether we can resolve the fundamental physics issues which is efficiency and heat.
Just yesterday I had to connect my phone to a friend's USB connector in his car but couldn't because the only cable available were the freak that is one standard in one end and another in the other (IE. a standard iPhone cable with USB -> lightning).