But it's 2880x1800 natively, it gets scaled down to look nice and have an appropriate size.
The problem is the hardware can't handle doing that. Simple tasks like web browsing cause stutters and lags. Trackpad becomes unresponsive. And the retina gimmick blurs UI assets on various non-retina applications.
A 2880x1800 is most useful when the hardware can handle it, is energy efficient, and the display is large enough to display the text legibly at native resolutions.
Otherwise, Apple is playing tricks to sample visual data across resolutions so it can be packed to 1920x1200. The end result is incompatibility across many software.
The introduction of "Retina" , on average, has decreased quality than increased it. If all you do is use safari (or an equivalent browser), look at pictures, and type using iWork pages, then you're not the type of user who will care.