Apple has done what they call the "retina" display on the iPhone, the iPad and the mac book.
the rest of the hardware vendors have not even come close to that.
small screens like the iPhone have had 200 ppi for a while now. time for the larger ones to catch up.
Take a mid-grade Android phone from 2 years ago, blow it up to 9.7", 15", and 17" and you have a "Retina" display. And the pixel density of the "Retina" display on the iPhone has been surpassed long ago.
To say that "the rest of the hardware vendors have not even come close to that" is just plain silly, especially since Apple doesn't even manufacture any of these displays.