Usb C has pins for both 3.x/4 and separate ones for usb 2.0. Many devices just hook up the 2.0 lines and call it a day, because parts that can actually handle 3.0+ are rare and expensive.

Companies making USB capable parts typically contract out or buy the section of their chip which handles USB or other things like ethernet (Intellectual property cores or IP core) already designed as a drop in part of the semiconductor… This usually is under some form of contract / nda + they pay a big fee, so the parts are expensive and documentation can be tough to acquire without yourself signing NDA and being a company looking to use their ICs.

USB 2.0 is much simpler and cheaper to deal with and cant handle as much bandwidth, but thats typically acceptable for simple electronics.

So the USB connector and the USB protocol are different, and not necessarily related to each other - however there is a functional upper limit to the throughput that a given connector type can support (you’ll never get USB 3.0 data transfer through a USB Mini connector).

A type C connector might only be wired to USB 2.0-level hardware on the back - but this is not really a bad thing. There are lots of low-level electronic devices that need a USB connector that don’t really need 3.0 data transfer, and faster data processing chips are more expensive, but it’s convenient to only need one type of cable for everything.

There are some nice reference tables in the Wikipedia article: USB Hardware

on a pc, yes, they are generally are some sort of usb 3 (like 3.2 gen 1 or gen 2).

as a connector, though, usb type-c is used for more than just usb.