And it would be a big bet for AMD. They don't create and manufacture chips 'just in time' -- it takes man hours and MONEY to spin up a fab, not to mention marketing dollars.

AMD has been producing GPU compute cards (and is highly sucessful at it) for nearly as long as nVidia. (https://www.amd.com/en/products/accelerators/instinct.html)

AMD is fabless. They spun off GlobalFoundries years ago.