Regarding your edit: Your statement is almost true that 4k Netflix is streamed TK you at a lower data rate than a full bandwidth HDMI 2.1 stream. However, viewing that movie would take the lossy compression from the Netflix stream, decompress it at the receiver, then do a second lossy compression to stream it wirelessly to the tv, where it is decompressed a second time. There will almost certainly be quality lost.

However this scenario totally ignores use cases that aren’t streaming movies. 4k BluRay is one example that could lower quality, but a bigger one is gaming. Pushing a 4k display at 120 hertz will fill that 48 GHz bandwidth of a wired connection. I presume the frame rate will suffer as a consequence of the shift to wireless interconnect.

Without any documentation, I acknowledge that I’m speculating, but it is informed speculation.