Especially seeing as Mountain Lion doesn't really have a concept of a universal "retina-like" resolution. Regular apps are just pixel-doubled (like iPhone apps on an iPad) and you have to write special code to use the high resolution. Think about it as addressing a special graphics card that has special drivers per application.
So, while Apple has that beautiful hardware, OSX is still not as good as Windows 7 (and 8) handling different resolutions.
I don't think that's strictly true.
If you have used ObjectiveC/Cocoa to write the application, then the special code is little more than adding high-res artwork and any custom UI elements you've written to the bundle and letting the OS pick the right set. This is why quite a few apps were made 'retina-ready' before the new Macbook was launched; that, and the fact that Apple has been brow-beating its developer community to use relative positioning on layouts for years. The notable exceptions will be apps that don't use the Cocoa frameworks the way Apple intended or don't use it at all: Adobe CS (though they are aiming to fix this as soon as possible) and Google Chrome (Google is already working on it apparently).
When the user picks a particular screen resolution, OSX will actually render the screen at the next higher supported resolution and then scale the UI elements and artwork for that resolution downward on the fly, rather than trying to scale existing artwork upward. And from the folk who have looked at it already, the effect is quite stunning. You basically get a pin-sharp UI at non-native resolutions. A rather interesting take on the resolution independence problem. When it comes to supporting higher resolutions in the future (if there is a need), the developer supplies more artwork and the operating system works out the details. RI has been an obsession of Apple's for years, and I don't think they're quite done with it yet.
Now when I select non-native resolutions on my Win7 box, the effect is not all that pleasing, so I'll be interested to see what the same trick looks like on the new Macbook.
For me though, this wasn't the most interesting news from the WWDC. If I were an IT pundit then I'd pay a lot more attention to what Apple has planned for Passbook. With all the excitement over the new laptop, the maps, the crap upgrade for the Mac Pro; the IT press missed that Cook mentioned Cupertino has 400 million active credit cards on file – and he felt the need to mention it twice.