We're wishing for a screen with such a high pixel density it makes pixels a completely irrelevant implementation detail of the screen itself. So nobody would be

We're wishing for a screen with such a high pixel density it makes pixels a completely irrelevant implementation detail of the screen itself. So nobody would be setting their font size (or anything else) as some number of pixels, they would in fact set it in a real physical unit like cm/inches and that choice merely comes down to personal preference, eyesight and how far you are from the screen.