In the US, Mac is now 16% marketshare. This is expected to increase a lot after Apple Silicon.that maybe, but again different markets. Also considering windows OS has a far larger share in the market than macOS and a market where AMD CPU’s are a part of I don’t see AMD being scared of apple, maybe if intel is extinct one day perhaps ( I wish)
So imagine one day the Mac has 50% market share (same as iOS/iPadOS). The market becomes 50% smaller for AMD.
So yes, AMD is afraid. Intel is too. Anyone who chooses a Mac would not be using an AMD/Intel CPU.