pretty sure amd just licenses the design and gets royalty on each card. its the individual companies like xfx bfg etc that make money on each card
AMD manufactures every single GPU at TSMC in Taiwan, then sells the associated chips, voltage controllers, etc. needed to build the reference design to companies like Asus, Sapphire, XFX, etc.
After a few months have passed, those companies usually make their own modified version with improved coolers, VRM's, PCBs etc. which means they don't have to order those parts from AMD.
The only part graphics card companies "need" is the GPU chip itself, they can build everything else from the ground if they want to (like in the case of the Sapphire Extreme cards which are completely different from reference cards) and make extra profits