Here’s the gut-punch for the typical living room, however. If you’re sitting the average 2.5 meters away from a 44-inch set, a simple Quad HD (QHD) display already packs more detail than your eye can possibly distinguish.

That seems in line with common knowledge? Say you want to keep your viewing angle at ~40º for a home cinema, at 2.5m of distance, that means your TV needs to have an horizontal length of ~180cm, which corresponds to ~75"

For a more conservative 30° viewing angle, at the same distance, you’d need a 55" TV. So, 4K is perceivable at that distance regardless, and 8K is a waste of everyone’s time and money.