@hexed notch your price estimate for the screens is actually way off. The screens they are using are 65 dollars each at low scale, and at a larger scale are probably closer to 50 dollars a screen.
I know this because valve seems to be using very similar screens to the leap motion project North star screens.
These are the screens project north star is currently using.
https://www.smart-prototyping.com/Display-for-Project-North-Star-3_5inch-1440x1600-pixels
A good thing to remember is that unlike consoles (which have a constant revenue stream from games), these devices need to make money (at least for now). Almost all of the current main teir consumer VR and AR headsets, cost about 50% or less of their total price to build.
I would currently estimate that the index costs about $240 dollars to build each one.
Also a little note is that the 144hz overclock is not the full overclock if they are the same BOE screens, the technical limit is actually 240hz, but the pixels will probably not last as long.