To put it into better perspective, put the resolutions into google:

(1920 * 1080) / (2880 * 1800) = 0.4

Your 1080p 15" display contains just 40% of the pixels of a single Retina 15" display. They even showed this in the demo. They edited a 1080p video in Final Cut at full resolution and there was plenty of room left for UI elements.

Apple is definitely the first to put a display of this density into a consumer product, or maybe any product.

> Just so you know, a whole bunch of laptops have been coming with "retina" displays for years now. They'd call it a "Full HD" laptop so it doesn't sound as shiny, but it's still a 15 or 17 inch screen with a 1920x1080 resolution.

That is different, though. 1080p on a 15" display is 146PPI; a "Retina" display (2880x1800) is 226PPI. That's a significant difference.

But people haven't been running those in 2x mode, so they don't require special design.

Indeed, my last 2 dell laptops were 1920x1200 with 15" screens.