Triple the DPI? Are you doing the calculations right? The DPI of this screen is 189. The iPad Standard, Air, and Pro at 11 and 13 inches have a DPI of 264. The iPad Mini is a standout at 326 DPI, which is 1.72x the DPI.
You are correct; I am using number of horizontal lines rather than computing the actual DPI. But this barely changes my argument, since even when they are at screens of similar size cheap iPads have double the number of horizontal lines. I have updated my post to reflect that.
