When I list all the devices I use, Macs, ThinkPad, Nintendo Switch, iPad, Pixel 6, work phone (it's some Motorola Android phone), and iPhone 13, only one of them uses a port that's not USB-C. I didn't realise it until now, but the same applies for peripherals and accessories. The only non-USB-C (wired) accessory I use is my wired EarPods.
For ages, people arguing against USB-C on the iPhone have told me some variant of, "us nerds might have other USB-C devices, but it's still too new for most people." While there may have once been an argument for this, I think that window ended ages ago. Who at this point is unfamiliar with USB-C?
Most iPhone users have Windows computers, which if they've bought in the past 5-6 years almost certainly included USB-C and charges that was as well.
iPhone users who use a Mac will have USB-C on their Mac if they bought one in the past 6 years. On most of those Macs, USB-C was literally the only port.
And speaking generally, the most mainstream products from the past 5 years all use USB-C. The Nintendo Switch is a phenomenon, basically all wireless earbuds besides Apple's, remotes, fitness devices, every phone that's not made by Apple, iPads…hell even the Lightning cable that ships with iPhones these days requires USB-C on the other end to charge.
Of course changing ports will cause some amount of pain, but I think at this point the only group who will really be confused by USB-C are people who have not bought another tech device in the past 5 years. Is that the group of users we should optimize iPhone tech around?
I know ordinary people in my life who don't use social media or follow tech news at all and they are getting annoyed with the iPhone using "Apple proprietary port" instead of what everything else uses. This is anecdotal, of course, but this wasn't a thing I heard 5 years ago, and now it comes up all the time when I talk to people about what they like/dislike about their iPhone.