becausewith that res you get high enough pixel density that you don't see pixels and you get nice sharp pictures without the need for AA and crap like that, just nice sharp images.
his ideal is unrealistic for the moment though. in the future it will happen, and not because he said this, but because people want the nice clean sharp images they have on devices like the ipad and higher end Androids.
Yeah, Toshiba just showed off a 20 inch panel with a res of 3840x2160 (so a "4K" resolution) a few months ago for a future tablet, eventually that tech will work it's way to desktops.
And we're finally getting to the point where desktop operating systems can handle the increased density, Windows has always had issues with it, but they made a big push to fix it with 8.