Yeah, 6 inches is about the furthest something can be for me to see it with any clarity at all without glasses, regardless of size and resolution, but still often read without them on my phone just to relax my eyes (and also, nothing looks clearer to me than something a few inches from my face with my glasses off)

But i did say “6 inches to a foot” which I’m at least assuming is not that atypical a range that people hold their devices at, but I’m not that great at judging distance overall… At the very least, my point is you’re holding the small device much closer than the bigger screen will be so needs higher PPI to still look as crisp