I don't know why there aren't independent X86-64 manufacturers. Patents on the extensions maybe? But as I understand copyright, APIs can't be copyrighted so it's not that.
The original ARM 32 stuff is clearly out of patents and is not being copied. And it doesn't require new extensions to be commercially viable.
The original ARM 32 stuff is clearly out of patents and is not being copied. And it doesn't require new extensions to be commercially viable.