The article raises the specter of a "1x-tax", along the lines of the "IE7 tax". The difference, of course, is that it's easy and free for people to upgrade their browsers, whereas upgrading the screen is not. As inconvenient as it is for the designers, it would be incredibly bad PR to say, in essence, "Only rich computer users should be using our site".
That should really not be a problem. Websites and apps can detect and load appropriate images for 2x or 1x displays. Same for apps. You design for 2x, and downsample for 1x.
Native apps, maybe, since you'd probably have to include both versions in your download. But surely its a bandwidth saving for web apps? You just let the browser download the right size image. Now your low res users get low res icons, while high res users get high res icons. Less bandwidth than just sending everyone the high res icons, or both sets.
