>>388478103
Looks like those aren't pancake optics either which makes sense if they wanted to demonstrate that brightness. In reality, pancake optics are less than 12.5% efficient due to imperfect components. Assuming 10% efficiency, that's still 1600 nits which is very high.

>>388478579
Apple's third layer is speculated to be a MTF enhancing layer rather than for adding an additional bounce to reduce form factor. 

>>388480356
>>388479929
I'm guessing this presentation is about a paper (typically what gets presented at SIGGRAPH), meaning that they probably didn't just simply overdrive the displays, but are doing something more that others can take learnings from. Otherwise there wouldn't be a paper.