The "pop-ups" (volume, surround mode, input) are superimposed onto the video signal, which is much easier to do with a simple composite or s-video 480i signal. When you move up to a component 480i, 480p, 720p, or 1080i signal, there's a lot more data involved in the video signal and overlaying data onto the incoming signal without degrading the input is a pretty tall order. OSD over component for the setup menu has become fairly common, but in general it is still done just as the 990 does it - by simply replacing the signal with a 480i signal carrying the menus.