He's not talking about resolutions provided (and my Vaio has a 1920x1080 15" display if you're looking for examples there) he's talking about support for different DPIs.
Windows 7/8 "kinda" work in this regard - I have to use accessibility addons in firefox to make it play nice, IE just stretches everything, I have no experience with OSX.
The main problem is third-party apps that don't respect the settings. It's not a huge problem. I've noticed some of the UI elements in windows get distorted sometimes too.
Changing DPI settings still screws up various applications on Windows 7 (fonts on various UI elements don't scale consistently, e.g. Visual Studio 2010 is messed up, games are usually completely broken even modern ones like Starcraft II, etc.) and overall make the system very frustrating to use (especially annoying since I have a pair of IBM T221s capable of 3840x2400). That being said it's still worthwhile when I'm in e.g. Lightroom.
