The display panels used for AR(and some pre-Oculus VR) displays are completely different thing from normal LCDs. Lots of them used to be a reflective panel made of silicon wafers with RGB front lights flashing in sequence. Driving circuits and interfacing protocols are all non-standard, under NDA, and quite complicated. The panels also needs to be coupled to a complicated optical lens - they're just magnifying glasses, only fancier. The complete thing that has a digital input and an optical output is often referred to as an Optical Engine.

What that means is, these glasses are made by someone paying $$$ once to Asian engineering companies to have it figured out, and everyone reuse that exact setup for years on.

And companies like Sony or Canon, they develop stuffs by scraping engineers off a wall instead of first throwing them at the wall, so every Sony or Canon cameras and projectors come with novel viewfinders and crazy patented lenses. Or panel suppliers like Kopin, Epson, or Sharp can arrange contacts to engineering consultants. I guess. Same likely goes for all the Chinese companies too, though I'm not familiar enough on that front to be able to offer googlable keywords.

Startups and even mid-sized consumer electronics companies don't have that kind of time or financial backings or margins to do the same. They barely manage to pay for assembly and ship it. And so the spec of the final product is whatever spec of parts that they could buy off the shelf.

What about Apple? Well, they pay to have 2 extra display factories built for redundancy by policy - I'm sure that most military organization don't do that. And even then they use a rather simplistic, completely concentric and rotationally symmetric optical design.

(I kind of have a crazy idea to bypass some of that, but unfortunately I'm crazy and so is the idea)