I'm sure amd could make a monster arm chip but without an oem who would put it in a laptop or desktop and without killer arm apps for windows whats the point?
Apple has the vertical integration to do it properly. Amazon and Microsoft have the server cloud computing to do it server side.
Without proper coordination from Microsoft, third party OEMs, and AMD they'll all fall behind on computing on end devices.
I think that's part of the reason AMD/Intel will be less relevant, the incentives and market moves don't look good for them.