Great points. While it's market is limited, I think Skully [0] is an interesting case of where AR can be more than just an entertainment device, in fact becoming a much more valuable safety device.
I think this is really under rated. Imagine how many telephone engineers who look at one of those junction boxes and want to know which telephone wire is hooked up to Mr Jones house? Or a mechanic who wants to know what spanner to used on a bolt. Or a nurse who wants to know a sleeping patients bio rythms. Or emergency responders who want to glance at the disaster and see routes through it to victims.