Usb4 does not define "type-a" connectors, thus type-a by definition is not "concurrent" with type-c in the usb spec. It is deprecated/legacy (ie still in use but not supported by newer versions of the spec)
That's very much not how USB version numbers works. Each version replaces a previous version "within the same generation", while guaranteeing backward compatibility with USB 2.0 (at least for the foreseeable future, given that it's unlikely that devices that only need USB 2.0 features will ever disappear).
- The USB 3.2 standard replaced 3.1/3.0, but explicitly did not replace USB 2.0
- Similarly, USB 4 guarantees USB 3.2 and USB 2.0 compatibility.
It doesn't matter that USB 4 does not define a Type A connector for USB 4 connections: a USB 4 controller can accept Type A on circuitry that's designed to operate in USB 2.0 compatibility mode.
