Haven't we had this discussion way too many times before? How many HN stories have there been of "look at the feat of content creation this person pulled off with an iThing!"?
Specific varieties of work are best suited to the desktop computing UI paradigm. That's distinctly different from "iThings are just content consumption devices." It's insufficiently rigorous thinking; also it's bullshit.
Warren Ellis has written tremendous amounts of his serious work on a (non-iOS) mobile device. Mark O'Connor made an iPad his primary coding device [1]. Atomic Tom could perform a song off of just iThings as instruments on the subway.
Please stop repeating the 'mobile devices are just for content consumption' meme. It's bullshit.
1: http://yieldthought.com/post/12239282034/swapped-my-macbook-...