We put in a lot of effort into the optics and we use variable magnification tech to get the most out of our displays (i.e. there's more pixels per degree in the foveal region, and less in the periphery where you can't see them anyways).

The drawback is that the optical train is long and there's 3 complex lenses as opposed to 1 glued assembly (not sure if it's 1 or 2 lenses). Adds per-unit cost and assembly labor, and at a $300 ($800 realistically) price point that's a lot.