DaveMebs: My point is that an ARM archtiecture license is not necessary for Microsoft to port Windows to ARM. There are only 3 or 4 ARM architecture licensees in the world. The architecture license allows the licensee to MODIFY the ARM instruction set/architecture and create their own implementations of the ARM architecture.

Microsoft does not need this simply to port Windows to ARM.

Therefore I think it is an interesting question: Why did Microsoft buy an ARM architecture license?