Does this mean that you haven't seen a desktop OS UI that doesn't look like crap? All desktop operating systems have to deal with different resolutions as they have to support different monitors. Even laptops generally have a video output for a second, unknown-sized monitor.
Ah, I see what you mean. Yes, fair call - you see this a lot in games, where the interface is based off static images - as you increase the resolution for better main view experience, the UI shrinks along with it, and it's tough if you like a high res main view but want larger control surfaces.
That being said, I have seen some games with nice UIs that scale appropriately with resolution, that is, changing resolution doesn't change the screen size of the controls. I can't for the life of me think of any at the moment - they're not that common, but they do exist.
OSX is not resolution independent, the UI shrinks when the resolution increases. This is not the case for Windows 7 (and older versions) though, dont know about Linux.
True, but it's the absolute size (in pixels) that matters on the desktop because the mouse (a pixel precise) pointing device is used. This becomes a problem on touch based devices with limited screen real estate where balancing info density and usability is crucial.