> And it comes at the cost of having to process all of those pixels.

Totally agree. I wish they had stopped at 200ppi phones. I don't understand the logic to spend cpu/gpu horsepower and mwh on a mobile display. I like my phone (LG G6) but really wish I had the battery life and performance dropping the resolution to 1080p would give me.

Given a pixel isn't a perfect colour dot, it has subpixel patterns and there is space between pixels; there is an advantage to having substantially higher pixel count than we can perceive.

What we really need are better up-scalers and a smarter dynamic trade-off between spatial/temporal display resolution. E.g. upscale from half res using something like Edge-Directed Interpolation ( https://people.xiph.org/~ds/edi/info.html ), render unchanged elements at native res, reduce rendering resolution when needed to maintain always lock with screen refresh rate.

With cheap hardware neural network accelerators, we could make use of very high spatial and temporal resolution displays without needing to actually render at 8k/240hz etc.

Not only VR but when pixels are smaller than the area needed to produce light they can become invisible like adverts that wrap vehicle windows. Lets us have cameras and other sensors behind the entire screen.

I imagine you could also carry around a physical loupe and use it to pixel peep instead of doing it in software (e.g. when processing photos)!