What would be coming in the future, though, that we'd have to do it "right"? If this is good enough that people can't see pixels, do we ever need to go higher? Resolution seems like one of the few features that has a limit, so this "hack" may in fact be the most elegant and simplest solution for now and in the future.
Hopefully, it's the first step towards truly resolution-independent interfaces. Imagine differences in screen resolution being differences in quality, as opposed to scale. Of course there will need to be a lot of research into UI/UX to make the most of the opportunities.
In a way, when referring to monitors, the word 'resolution' is in itself a misnomer, as we're not actually talking about density but instead about absolute pixel measurements.
Imagine differences in screen resolution being differences in quality, as opposed to scale.
That's exactly what this is, though — the window decorations, for example, in OS X on the new MBP are identical in size to the ones on the "old" MBP, they're just more detailed.
And since they're so detailed (hence "retina display" moniker) that most people won't be able to see any pixels at all and, since in just a few years, all displays will obviously be "retina displays", I think there's a strong argument to be made that resolution-independent interfaces aren't ever gonna happen and that that's not a bad thing at all. (They've been tried for years and they always end up a burden for the developer and/or not working well for the user.) The limitations of human biology make it so that this simple "hack" is actually the easiest for developers, works the best for users, and won't ever need to be replaced. … OK, yeah, one day we'll all have bionic eyes and we'll have to do the same doubling trick again, but presumably "Bionic-Retina Displays" will be cheap to produce by then. :)
Without completely eliminating all parameters to Cocoa and CoreFoundation drawing functions that take measurements in pixels and instead using pixel-less measures (sort of like how we specify font size in pts), this is always going to be a "hack".
