Having read the article, I'm still not able to fully grasp why the old techniques for improving text legibility can't be "scaled" with screen resolution. We had

Having read the article, I'm still not able to fully grasp why the old techniques for improving text legibility can't be "scaled" with screen resolution. We had imprecise pixels before and we still do, in the sense that they are very finite. I totally get why smoothing and other tricks aren't as necessary as they used to be, but I don't get why they have to be detrimental on Retina displays. At what resolution does this reversal happen and why?