Maybe I missed something, but I don't think Apple discussed speed, charging, USB-PD/PPS/etc support in regards to USB-C as a connector and an ecosystem.
The discussion on iphone moving to USB-C is far from over.
The new processor featured in the Pro models adds support for USB 3.0 transfer speeds. Apple started doing a thing last year where the non-Pro phones get last year's processor, and only the new Pros get the new one. So it's likely next year the entire lineup will get the faster transfer speeds.
Just to update a day later, I hadn't processed during the presentation that the new processor is named A17 "Pro," not "Bionic."
So my theory now is next year the non-Pro iPhone 16's will have an A17 Bionic that doesn't have the faster transfer speeds. It seems like Apple considers the fast transfer speeds a purely Pro feature, pretty much exclusively for ProRaw photos and ProRes videos. For all other use cases, I think they'd rather incentivize people to use AirDrop and iCloud for moving files around.
10Gbps is perfectly reasonable given the devices cap out at 1tb. If people can tolerate iPhones taking hours to charge, I doubt they're going to mind the minutes a wired data transfer takes.
480Mbps is so bad you're better off using Wifi in every situation I can think of.