They didn’t downgrade anything…
iPhones have the USB controller as part of the SoC. Not a separate controller like the iPads or laptops. They don’t have the space for it.
The non pro this year is using last years pro chip which didn’t have a USB 3 controller on it. For the non pro they are repinning the port to USB c to repurpose the controller on the chip. But they physically cant add USB 3 to it.
They also never removed cameras from the non pro model either. Idk where you pulled that from. The XS and XS Max both only had two cameras, and when they went to the iPhone/iPhone Pro model with the 11, the non pro still had two and they added a third for the pro.