Transport is a classic example of economies of scale

You did not address the underlying point that I made which is you are implying scaling economies across continents is not scaling "an" economy but forcing different economies to merge. You/your friend would also get a lot more sympathy if you acknowledged any of the legitimate points regarding the actual technical difficulties in what you are talking about MS doing.

MS of NZ does not have access to the customer information for computers registered in the US (different laws regarding handling customer information is one issue). I base this off of questions I asked and had answered when I traveled and had trouble with my Surface.

So is it reasonable? Is it Simple? No. MS probably isn't anticipating having to ship computers to NZ from their US parent company when they explicitly created a NZ/AU subsidiary to handle this.

Could MS create a new branch specifically to handle international shipping and customs? Yes. But then again considering these are fringe cases, your friends probably the most fringe-ish I've ever heard (Purchased in Dubai, registered in the US, and used in NZ).

Economies of scale right? This problem doesn't have a very large scale. What exactly do you expect them to scale up?

And if you are purchasing a computer, and moving it around the world, 5-10 minutes of checking what the warranty program is (especially international) is absolutely reasonable for the average consumer.