Note that for (1), you're going to have to explain your logic there, because retina displays still need subpixel rendering. They're nowhere near the print industry's standard 300 dpi, they're (a little less than) 300 ppi. For a "three different colours arranged in in blocks of four" screen, you'd need closer to 1200ppi before "we don't need subpixel rendering" is actually true. Until then, the raster tragedy may become less noticeable to people who are used to reading simplistic orthographies (like English), but it's very much still there for more complex orthographies (like, say, almost every middle-eastern, asian, and east-asian orthography)