My understanding is that on pre-retina displays, subpixel anti-aliasing was a fairly difficult, complex, and resource intensive technique that resulted in huge

My understanding is that on pre-retina displays, subpixel anti-aliasing was a fairly difficult, complex, and resource intensive technique that resulted in huge improvements in readability, and in the era of retina displays, it is a lot of complication that results in barely perceivable gains.