Disappointed by the discussion so far. The response seems to be "Trust Apple". The OP's claims are more theoretical and apply to any headset - is there a decent rebuttal of this article? (I am not an expert, I just want good information)
The kguttag.com blog posts were the first time I've seen someone raise interesting questions about the feasibility of the product and try to poke holes in them. Yes, he's using product shots and statements from Apple to speculate what the product's limitations are, but this guy appears to have knowledge about this space himself, so he's familiar with the difficulties of building AR and VR headsets.