>We also believe the race for ever higher resolution has become a distraction. Beyond 300ppi you’re adding overhead rather than improving display clarity.

This isn't completely true, higher PPI improves readability (and looks) of the text that's written using more complex characters like Chinese Hanzi or Japanese Kanji even beyond that line at smaller distances. Here's an image that illustrates this:

http://cdn.physorg.com/newman/gfx/news/hires/2011/1-toshibab...

Not to mention it's useful for displaying 1080p without losing information.