When people stop buying cheap bric-a-brac with just-enough-for-youtube-480p integrated graphics from HP and Dell for 499.
1024x768 -> 1280x768 -> 1366x768
but the trend reverses at the high-end: 2048x1536 -> 1920x1200 -> 1920x1080
Apple's 2880x1800 display is an exception, but so far the rest of the industry doesn't seem to be trying to imitate it.Even the cheapest comes with a dual core processor, though, so you can share your memory among 2 cores and an integrated graphics engine. Progress it ain't.