Here are some numbers to blow your mind: The original Macintosh, released in 1984, had a monochrome 512 × 342 pixel display. That was 175,104 points. Today, the icons on iOS are 512 x 512 pixels, drawn from a 16.7 million color palette plus 256 levels of transparency.
28 years ago, a monochrome icon on the Mac was 16 x 16 pixels. It only took 32 bits of memory. Compare to the 512 x 512 pixels of each iOS’ icon. It takes four times the total video memory of the original Mac to represent a single icon in iOS at full size. Of course, iOS’ icons are not shown on screen at that size. They are much smaller. Eventually, however, you can be sure that there will be displays that would require that insane pixel density.