That's an interesting point of view!
As a UX designer veteran, you must know these numbers better than most of us here, do you know how ubiquitous retina screen are?
On desktop, the Firefox Hardware report [1] tends to show that they the most common resolutions are 1366 * 768 and 1920 * 1080, this unfortunately doesn't tell us if those are retina screens or not, but from [2] it seems that we're talking about at most 17% as a 'retina' display would report as 1920 * 1080