Times are much different now, and it's doubtful that Apple really "needs" any additional revenue from actual computer sales to survive since they have the iPhone now.
What evidence is out there that they will license the OS?
Why just AMD?
Your points and historical recollection are well noted. These days their desktop computer sales mean less to them. They probably make more from iPhone cables and cases. There's also no direct renevue earned from selling the OS. It's free and they don't even act against pirates.
We take a look at the following clues (tip of the iceberg).
- PC graphics cards now show a loading screen without the need for a Mac EFI ROM. This is important if you want to allow macOS to run on PC hardware. Apple could have maintained the EFI necessity easily, so it's important to ask why this change has occured.
- But you also don't want OEMs installing macOS on any PC otherwise they'll choose Intel. But Apple has a relationship with AMD now that goes beyond just graphics. So making an AMD motherboard a condition for installing macOS makes sense.
- But why not Intel? And why has Nvidia been neglected so badly (surely a court case wouldn't matter that much). We now come to Apple's future plans - the automotive.
Here they face competition from Nvidia and Intel who are both pitching their solutions for the future of transport. It's going to be a massively profitable industry once it really takes off, revolutionising personal vehicles, public and commercial transport. If Apple wants to compete, even win, in this space then it has to reduce some revenue flow to its competitors.
AMD is absent from that space. Apple can use AMD's solutions to help achieve the above goals. Intel and Nvidia will have less financial clout to compete after Apple makes a move away from their products. I would not be surprised to see:
-ARM based Apple notebooks
-macOS freely installable on any computer with AMD motherboards
-Apple automobile using ARM processors and AMD compute modules