A typical high resolution display of what physical size? Using the resolution is meaningless, it's the DPI that's important in this case.
Also, the 2x is not really marketing copy. It's the number of physical pixels that make up each geometric "point" in an Apple retina display. Ideally applications and operating systems would be truly resolution-independent and this ratio could be any decimal number. In such a world, you could chose how to use your screen's resolution - for more space or for smoother rendering of on-screen elements.
Apple's solution is a hack that uses an integer ratio to make backwards compatibility easier. With a 2x ratio you can blow up a point from a non-retina app to exactly 4 pixels, avoiding some hairy rendering issues.